Liver x receptor modulators

ABSTRACT

Provided herein are novel compounds and pharmaceutically acceptable salts thereof that are liver X receptor modulators. Also provided are compositions comprising compounds of the invention and a carrier. Additionally, use of the compounds herein and methods for treating a disease or disorder associated with the liver X receptor are further described.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/385,688, filed on Sep. 16, 2014, which is a 35 U.S.C. §371 nationalstage filing of International Application No. PCT/US2013/031242, filedMar. 14, 2013, which claims the benefit of the filing date of U.S.Provisional Application No. 61/612,051, filed on Mar. 16, 2012. Theentire contents of the above applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to compounds that modulate the activity ofliver X receptors.

BACKGROUND OF THE INVENTION

Atherosclerosis is the leading cause of death in the developed world,and atherosclerosis is predicted to be the leading cause of death in thedeveloping world in the 21st century. Liver X receptors (LXRs) areligand-activated transcription factors that play a crucial role inregulating the expression of genes involved in lipid metabolism andcellular cholesterol homeostasis. LXR agonists have been shown toenhance reverse cholesterol transport (RCT), facilitating cholesteroltrafficking from the periphery back to the liver for processing andexcretion. RCT occurs via upregulation of cholesterol transporters(ATP-Binding Cassettes: ABCA1 and ABCG1) in peripheral macrophages.Active RCT has the potential to inhibit the progression ofatherosclerosis.

There are two isoforms of LXR, LXRα (NR1H3) and LXRβ (NR1H2) that areencoded by separate genes. LXRα expression is tissue-selective,detectable in liver, intestine, kidney, adipose tissue and adrenalglands, all of which are important for lipid homeostasis, whereas LXRβis expressed ubiquitously. Both LXRs require the retinoid X receptor(RXR) as an obligate heterodimer partner to recognize and bindcooperatively to LXR response elements (LXREs) consisting of two directrepeats of a core hexameric sequence spaced by four nucleotides (DR4).The ligand binding domains of the two LXRs are fairly well conserved(˜78% amino acid homology) and respond to endogenous ligands consistingof oxidized derivatives of cholesterol (oxysterols) that serve asintermediates in steroid hormone and bile acid synthesis. Among them,22(R)-hydroxycholesterol, 24(S)-hydroxycholesterol, and 24(S),25-epoxycholesterol are the most potent. These data suggested that LXRsare likely to play an important role in cholesterol regulation, whichwas later confirmed through gene knock-out studies in mice.Non-steroidal ligands have also been identified, and, using these aschemical probes many LXR-regulated genes have been discovered. SeveralLXRE-containing genes are involved in cholesterol metabolism, reversecholesterol transport (RCT) and lipogenesis. Other genes involved ininflammation and carbohydrate metabolism lack LXREs, but are repressedby LXRs in a ligand-dependent manner. Based on these discoveries, theliver X receptors have recently emerged as unprecedented targets actingas intracellular cholesterol sensors, providing the basis for thetreatment of a variety of diseases, including atherosclerosis, diabetes,Alzheimer's disease, skin disorders, reproductive disorders and cancer(Viennois et al., 2011, Expert Opin. Ther. Targets, 15(2):219-232).Additionally, it has been determined that LXR agonists modulateintestinal and renal sodium phosphate (NaPi) transporters and, in turn,serum phosphate levels (Caldas et al., 2011, Kidney International,80:535-544). Thus, LXR is also a target for kidney disorders, andparticularly for the prevention of hyperphosphatemia and associatedcardiovascular complications. Recently, LXRs have been identified astargets in the treatment of osteoporosis and related diseases (Kleyer etal., 2012, J. Bone Miner. Res., 27(12):2442-51).

Alzheimer's disease is one of the most common forms of dementia,characterized by the accumulation and deposition of amyloid-beta (Aβ)peptides in the brain, leading to the perturbation of synaptic functionand neuronal loss in the brains of affected individuals. Neurons in thebrain produce Aβ peptides via cleavage of amyloid precursor protein(APP), and Aβ peptides are normally cleared through efflux into theperipheral circulation and by degradation by proteinases within thebrain.

Apolipoprotein E (apoE) is associated with age-related risk forAlzheimer's disease and plays critical roles in Aβ homeostasis. LXRincreases the expression of apoE and increases the lipidation of apoE.Degradation of Aβ both intra- and extracellularly is enhanced bylipidated apoE. LXR agonist treatment stimulated proteolytic degradationof Aβ, reduced plaque pathology, and improved memory in APP-expressingtransgenic mice (Jiang et al., 2008, Neuron, 58:681-693).

In skin, keratinocytes are a critical component of the epidermis. Theouter layer, stratum corneum, is primarily responsible for thepermeability barrier to water and electrolyte transit. Keratinocytes inthe epidermis undergo differentiation which culminates in keratinocytecornification (“the bricks”) and in formation of the extracellularlipid-enriched lamellar membranes (“the mortar”) in the stratum corneum.Both LXRα and LXRβ are expressed in keratinocytes, and LXR expressionand activation promotes epidermis barrier function. Activation of LXR isinvolved in keratinocyte differentiation, formation of the lamellarmembrane and overall improvement of epidermal bather function. Thus, LXRactivation is expected to result in increased keratinocytedifferentiation, increased lipid secretion (via ABCA1, ABCA12), andincreased lamellar body formation, leading to a healthy epidermis(smooth skin).

The potential therapeutic utility of LXR agonists has led to thedevelopment of several high affinity LXR ligands with potent agonism forboth receptor subtypes. The therapeutic utility of LXR agonists isconstrained by their potential to induce lipogenic genes includingsterol response element binding protein-1c (SREBP1c) and fatty acidsynthase (FAS). Preclinical studies have demonstrated that syntheticmodulators of LXRs reduce lesion progression in murine models ofatherosclerosis with limited increase in hepatic lipogenesis. There is aclear need for new LXR chemotypes that retain the anti-atheroscleroticefficacy of current LXR agonists but are devoid of lipogenic activity.Compounds exhibiting a pharmacological profile with positive effects onRCT while being neutral or suppressive on lipogenic genes will bevaluable therapeutic agents in patients with atheroscleroticdyslipidemia.

The present invention provides compounds that are liver X receptoragonists and are useful as therapeutic agents for the promotion ofreverse cholesterol transport and the suppression of hepaticlipogenesis, and for the prevention, amelioration or treatment ofdiseases or disorders including atherosclerosis, Alzheimer's disease,dermatitis, and dyslipidemia in a patient.

SUMMARY OF THE INVENTION

Disclosed are LXR modulators that are useful as therapeutic agents forthe promotion of reverse cholesterol transport and the suppression ofhepatic lipogenesis, and for the prevention, amelioration or treatmentof diseases or disorders including atherosclerosis and dyslipidemia in asubject. The disclosed LXR modulators are selective for the LXRβ subtypeover the LXRα subtype (see e.g., Example 2, isomer 1 and Example 4,isomer 1).

One embodiment of the invention is a compound represented by structuralformula I:

-   -   or a pharmaceutically acceptable salt thereof.

X is N or CR^(c).

R¹ is alkyl or —NR^(a)R^(b).

R² is H; halogen; —CN; —NRC(O)R; —C(O)OR; —C(O)NR^(a)R^(b); monocyclicheteroaromatic optionally substituted with one or more groups selectedfrom alkyl, —CN, —NRC(O)R, —C(O)OR, —C(O)NR^(a)R^(b) and halogen;monocyclic non-aromatic heterocycle optionally substituted with one ormore groups selected from alkyl, halogen, —CN and ═O; or alkyloptionally substituted by one or more groups selected from halogen,hydroxy, alkoxy, —NR^(a)R^(b), —NRC(O)R, —NRC(O)O(alkyl), —NRC(O)N(R)₂,—C(O)OR, thiol, alkylthiol, nitro, —CN, ═O, —OC(O)H, —OC(O)(alkyl),—OC(O)O(alkyl), —OC(O)N(R)₂ and —C(O)NR^(a)R^(b).

R³ is alkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl,monocyclic non-aromatic heterocycle, monocyclic heteroaromatic orphenyl, wherein the phenyl, monocyclic non-aromatic heterocycle andmonocyclic heteroaromatic group represented by R³ are optionallysubstituted with one or more groups selected from alkyl, halogen,haloalkyl, alkoxy, haloalkoxy, nitro and —CN;

R⁴ is halogen, —CN, —OR, —SR, —N(R)₂, —C(O)R, —C(O)OR, —OC(O)O(alkyl),—C(O)O(haloalkyl), —OC(O)R, —C(O)N(R)₂, —OC(O)N(R)₂, —NRC(O)R,—NRC(O)O(alkyl), —S(O)R—SO₂R, —SO₂N(R)₂, —NRS(O)R, —NRSO₂R,—NRC(O)N(R)₂, —NRSO₂N(R)₂, haloalkyl, haloalkoxy, cycloalkoxy,cycloalkyl, monocyclic non-aromatic heterocycle, monocyclicheteroaromatic or alkyl, wherein the monocyclic non-aromaticheterocycle, monocyclic heteroaromatic and alkyl group represented by R⁴are optionally substituted with one or more group selected from —CN,—OR, —SR, —N(R)₂, ═O, —C(O)R, —C(O)OR, —C(O)O(haloalkyl), —OC (O)R,—OC(O)O(alkyl), —C(O)N(R)₂, —OC(O)N(R)₂, —NRC(O)R, —NRC(O)O(alkyl),—S(O)R, —S O₂R, —SO₂N(R)₂, —NRS(O)R, —NRSO₂R, —NRC(O)N(R)₂ and—NRSO₂N(R)₂.

Each R independently is H or alkyl.

R^(a) and R^(b) are independently H, alkyl or R^(a) and R^(b) can betaken together with the nitrogen to which they are attached to form amonocyclic non-aromatic heterocycle.

R^(c) is H, alkyl, or halogen.

Another aspect of the invention is a pharmaceutical compositioncomprising a compound of the invention and a pharmaceutically acceptablecarrier or diluent.

A further aspect of the present invention also provides for a method oftreating a subject with a disease or disorder that is treatable byupregulating LXR activity. The method comprises administering aneffective amount of a compound of the invention or a pharmaceuticallyacceptable salt thereof to the subject in need thereof.

Also provided in the invention is the use of a compound of the inventionfor the manufacture of a medicament for treating a subject with adisease or disorder that is treatable by upregulating LXR activity in asubject in need thereof.

Disclosed herein is also a compound of the invention for use in treatinga disease or disorder that is treatable by upregulating LXR activity ina subject in need thereof

DETAILED DESCRIPTION OF THE INVENTION A. Compounds

The compound(s) of the invention provided herein include both theneutral form and a pharmaceutically acceptable salt thereof.

In one embodiment, the compound is represented by structural formula II,III, IV, V, or VI, wherein the values for the variables are as definedfor Formula I above.

In a first alternative embodiment of any compound of formulas I throughVI, the variables are defined as follows:

R³ is alkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl or phenyl,wherein the phenyl represented by R³ is optionally substituted with oneor more groups selected from alkyl, halogen, haloalkyl, alkoxy,haloalkoxy, nitro and —CN; and R⁴ is halogen, —CN, —OR, —SR,

—N(R)₂, —C(O)R, —C(O)OR, —OC(O)O(alkyl), —C(O)O(haloalkyl), —OC(O)R,—C(O)N(R)₂, —OC(O)N(R)₂, —NRC(O)R, —NRC(O)O(alkyl), —S(O)R, —SO₂R,—SO₂N(R)₂, —NRS(O)R, —NRSO₂R, —NRC(O)N(R)₂, —NRSO₂N(R)₂, haloalkyl,haloalkoxy, cycloalkoxy, cycloalkyl or alkyl, wherein the alkyl grouprepresented by R⁴ is optionally substituted with one or more groupsselected from —CN, —OR, —SR, —N(R)₂, ═O, —C(O)R, —C(O)OR,—C(O)O(haloalkyl), —OC(O)R, —OC(O)O(alkyl), —C(O)N(R)₂, —OC(O)N(R)₂,—NRC(O)R, —NRC(O)O(alkyl), —S(O)R, —SO₂R, —SO₂N(R)₂, —NRS(O)R, —NRSO₂R,—NRC(O)N(R)₂ and —NRSO₂N(R)₂.

The values for the remaining variables are as defined for Formula I.

In a second alternative embodiment of any compound of formulas I throughVI, the variables are defined as follows.

R¹ is methyl or —NH₂.

R² is H or methyl, wherein the methyl group represented by R² isoptionally substituted with one or more groups selected from halogenhydroxyl, alkoxy, —NR^(a)R^(b), —NRC(O)R, —NRC(O)O(alkyl), —NRC(O)N(R)²,—C(O)OR, thiol, alkylthiol, nitro, —CN, ═O, —OC(O)H, —OC(O)(alkyl),—OC(O)O(alkyl), —C(O)NR^(a)R^(b) and —OC(O)N(R)₂. Preferably, R² is H or—CH₂OH.

R³ is methyl, ethyl, propyl, isopropyl, tert-butyl, sec-butyl,iso-butyl, —CH₂CF₃, —CH(CH₂F)₂, —CH(CHF₂)₂, —CH(CF₃)₂, —CF(CH₃)₂, —CF₃,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, —C(OH)(CH₃)₂,—CH(OH)(CH₃), or phenyl, wherein the phenyl group represented by R³ isoptionally substituted with one or more groups selected from alkyl,halogen, haloalkyl, alkoxy, haloalkoxy, nitro and —CN.

R^(c), where present, is H.

The values for the remaining variables are as defined for Formula I orin the first alternative embodiment.

In a third alternative embodiment of any compound of formulas I throughVI, R¹ is methyl; R² is —CH₂OH; and R³ is isopropyl. The values for theremaining variables are as defined for Formula I or for the first orsecond alternative embodiment.

In a fourth alternative embodiment of any compound of formulas I throughVI, R⁴ is halogen, hydroxy, alkyl, cycloalkyl, cycloalkoxy, alkoxy,haloalkoxy, haloalkyl, —N(R)₂, —C(O)OH, —C(O)O(alkyl),—C(O)O(haloalkyl), —C(O)(alkyl), —C(O)N(R)₂, —NRC(O)R, —SO₂N(R)₂,—OC(O)N(R)₂, —CN, hydroxyalkyl or dihydroxyalkyl. The values for theremaining variables are as defined for Formula I or for the first,second or third alternative embodiments.

In a fifth alternative embodiment of any compound of formulas I throughVI, R⁴ is alkyl, haloalkyl, cycloalkyl, alkoxy, or haloalkoxy. Thevalues for the remaining variables are as defined for Formula I or forthe first, second or third alternative embodiments.

In a sixth alternative embodiment of any compound of formulas I throughVI, R⁴ is methyl, ethyl, hydroxy, —CF₃, isopropyl, cyclopropyl, —CH₂OH,—CH(OH)(CH₂)(OH), —C(OH)(CH₃)₂, —CH(OH)(CH₃), —CH(OH)(CH₂)(CH₃),—CH(OH)(CH₂)₂(CH₃), —C(O)NH₂, —C(O)N(CH₃)₂, —C(O)OH, —C(O)NH(CH₃),—C(O)CH₃, —C(O)CH₂CH₃, —C(O)O(CH₂)(CH₃), —C(O)O(tert-butyl),—C(O)O(C)(CH₃)₂(CF₃), —NHC(O)CH₃, —OCHF₂, —OCF₃, —OCH₂CH₃, —OCH(CH₃)₂ or—OCH₃. Preferably, R⁵ is —C(CH₃)₂OH. The values for the remainingvariables are as defined for Formula I or for the first, second or thirdembodiments.

In a seventh alternative embodiment of any compound of formulas Ithrough VI, R⁴ is methyl, halogenated methyl, cyclopropyl, —OCHF₂ or—OCH₃. Preferably, R⁴ is CF₃. The values for the remaining variables areas defined for Formula I or for the first, second or third alternativeembodiments.

Another embodiment of the invention is a compound represented by formulaI, II, III, IV, V or VI or a pharmaceutically acceptable salt thereof,wherein the variables are as defined for formula (I) or in the first,second or third alternative embodiments, provided that the compoundcomprises at least one group represented by —C(O)OR.

Another embodiment of the invention is a compound represented by formulaI, II, III, IV V or VI or a pharmaceutically acceptable salt thereof,wherein the variables are as defined for formula (I) or in the first,second, third, fourth, fifth, sixth or seventh alternative embodiment,provided that the compound comprises no groups represented by —C(O)OR.

The compounds of the invention contain at least one chiral center and,therefore, exist as enantiomers. When compounds of the invention aredepicted or named without indicating the stereochemistry, it is to beunderstood that enantiomerically pure forms and mixtures of enantiomers,including racemic mixtures, are encompassed.

When a compound is designated by a name or structure that indicates asingle enantiomer, unless indicated otherwise, the compound is at least50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5% or 99.9% optically pure (alsoreferred to as “enantiomeric ally pure”). Optical purity is the weightin the mixture of the named or depicted enantiomer divided by the totalweight in the mixture of both enantiomers.

In a seventh alternative embodiment, a compound of the invention isdepicted by a compound in Table 1 or a pharmaceutically acceptable saltthereof.

TABLE 1 Compound No. Example No. Structure E1 Example 1

E2a Example 2, isomer 1

E2b Example 2, isomer 2

E3a Example 3, isomer 1

E3b Example 3, isomer 2

E4a Example 4, isomer 1

E4b Example 4, isomer 2

B. Definitions

Unless otherwise specified, the below terms used herein are defined asfollows.

“Subject”, “patient” and “mammal” are used interchangeably herein. Inone embodiment, the subject is a non-human animal such as a non-humanprimate (e.g., a monkey, chimpanzee), a farm animal (e.g., a horse, cow,pig, chicken, or sheep), a laboratory animal (e.g., a rat or mouse), ora companion animal (e.g., dog, cat, guinea pig or rabbit). In apreferred embodiment, the subject is a human.

“Compound(s) of the invention” refers to compounds represented byStructural Formula I, II, III, VI, V, VI; a compound depicted in Table1; a compound named or depicted in the examples herein as the finalcompound(s) of the examples; or a pharmaceutically acceptable saltthereof. “Compound(s) of the invention” also includes the neutral formof the compounds as depicted herein.

“Pharmaceutically acceptable” refers to a component that is, within thescope of sound medical judgment, suitable for use in contact with thetissues of the subject, such as humans and other mammals, without unduetoxicity, irritation, allergic response and the like, and arecommensurate with a reasonable benefit/risk ratio.

Included in the invention are pharmaceutically acceptable salts of thecompounds disclosed herein. The disclosed compounds have basic aminegroups and therefore can form pharmaceutically acceptable salts withpharmaceutically acceptable acid(s). Suitable pharmaceuticallyacceptable acid addition salts of the compounds of the invention includesalts of inorganic acids (such as hydrochloric acid, hydrobromic,phosphoric, metaphosphoric, nitric, and sulfuric acids) and of organicacids (such as, acetic acid, benzenesulfonic, benzoic, citric,ethanesulfonic, fumaric, gluconic, glycolic, isethionic, lactic,lactobionic, maleic, malic, methanesulfonic, succinic,p-toluenesulfonic, and tartaric acids). Compounds of the invention withacidic groups such as carboxylic acids can form pharmaceuticallyacceptable salts with pharmaceutically acceptable base(s). Suitablepharmaceutically acceptable basic salts include ammonium salts, alkalimetal salts (such as sodium and potassium salts) and alkaline earthmetal salts (such as magnesium and calcium salts). Lists of suitablesalts are found in Remington's Pharmaceutical Sciences, 18th ed., MackPublishing Company, Easton, Pa., 1990, p 1445, the disclosure of whichis hereby incorporated by reference.

“Liver X receptors or LXRs” includes both the α and β subtypes of theliver X receptor. In one embodiment, the disclosed compounds selectivelybind and upregulate the activity of the LXRβ subtype over the LXRαsubtype. To “modulate” a receptor means that there is a change oralteration in the activity of a molecule of interest, e.g., thebiological activity of liver X receptor. Modulation may be anupregulation (increase) or a downregulation (decrease) in the magnitudeof a certain activity or function of the molecule of interest. Exemplaryactivities and functions of a molecule include, but are not limited to,binding characteristics, enzymatic activity, cell receptor activation,transcriptional activity, and signal transduction. In an embodiment, thecompounds of the invention are LXR agonists that, for example,upregulate or downregulate genes which are transcriptional targets ofLXR (i.e., “LXR target genes”).

“Treat” or “treating” include both therapeutic and prophylactictreatments and mean to ameliorate, decrease, suppress, attenuate,diminish, arrest, or stabilize the development or progression of adisease (e.g., a disease or disorder delineated herein), lessen theseverity of the disease or improve the symptoms associated with thedisease.

“Disease” or “disorder” means any condition that is modulated orotherwise affected by LXR activity or in which LXR activity isimplicated. The diseases or disorders include those which are associatedwith, or symptoms arising from the complications of, altered cholesteroltransport, cholesterol reverse transport, fatty acid metabolism,cholesterol absorption, cholesterol re-absorption, cholesterolsecretion, cholesterol excretion, or cholesterol metabolism.

“Effective amount” is the quantity of the compound which is sufficientto treat (therapeutically or prophylactically) the target disorder or inwhich a beneficial clinical outcome is achieved when the compound isadministered to a subject in a proper dosing regimen. Effective doseswill also vary, as recognized by one of ordinary skill in the art,depending on the disease being treated, the severity of the disease, theroute of administration, the sex, age and general health condition ofthe patient, excipient usage, the possibility of co-usage with othertherapeutic treatments such as use of other agents and the judgment ofthe treating physician or other medical provider. For example, aneffective amount is sufficient to reduce or ameliorate the severity,duration or progression of the disorder being treated, prevent theadvancement of the disorder being treated, cause the regression of thedisorder being treated, or enhance or improve the prophylactic ortherapeutic effect(s) of another therapy. For example, when a compoundof the invention is administered to a subject with a cancer, a“beneficial clinical outcome” includes a reduction in tumor mass, areduction in metastasis, a reduction in the severity of the symptomsassociated with the cancer and/or an increase in the longevity of thesubject compared with the absence of the treatment. When a compound ofthe invention is administered to a subject with a disorder such asatherosclerosis, a “beneficial clinical outcome” includes reduction inthe severity or number of symptoms associated with the disorder, lowercholesterol, or increase in the longevity of the subject compared withthe absence of the treatment. The recommended dosages of agentscurrently used for the treatment of a disorder can be obtained fromvarious references in the art including, but not limited to, Hardman etal., eds., 1996, Goodman & Gilman's The Pharmacological Basis Of BasisOf Therapeutics 9^(th) Ed, Mc-Graw-Hill, New York; Physician's DeskReference (PDR) 57^(th) Ed., 2003, Medical Economics Co., Inc.,Montvale, N.J., each of which is incorporated herein by reference in itsentirety. In certain embodiments, an effective amount of a compound ofthis invention is in the range of from 0.5 mg to 2000 mg, or from 0.5 mgto 1000 mg, or from 0.5 mg to 500 mg, or from 0.5 mg to 100 mg, or from100 mg to 1000 mg, or from 20 mg to 2000 mg per treatment. Treatmenttypically is administered from one to three times daily.

“Halo” or “halogen” means chloro, bromo, fluoro, or iodo. In oneembodiment, halo is fluoro.

“Alkyl” means a straight or branched hydrocarbon group having 1 to 15carbon atoms in the chain. In one embodiment, alkyl groups have 1 to 12carbon atoms in the chain. In another embodiment, alkyl groups have 1 to6 carbon atoms. Exemplary alkyl groups include, but are not limited to,methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl,n-pentyl, 3-pentyl, heptyl, octyl, nonyl, decyl, and dodecyl.

“Alkoxy” is an alkyl group which is attached to another moiety via anoxygen linker (—O(alkyl)). Non-limiting examples include methoxy,ethoxy, propoxy, and butoxy.

“Haloalkyl” or “halogenated alkyl” means an alkyl group in which one ormore, including all, of the hydrogen radicals are replaced by a halogroup, wherein each halo group is independently selected from —F, —Cl,—Br, and —I. For example, the term “halomethyl” or “halogenated methyl”means a methyl in which one to three hydrogen radical(s) have beenreplaced by a halo group. Representative haloalkyl groups includefluoromethyl, difluoromethyl, trifluoromethyl, bromomethyl,1,2-dichloroethyl, 4-iodobutyl, 2-fluoropentyl, and the like. Otherexamples include groups such as but are not limited to —CH₂CF₃,—CH(CH₂F)₂,

—CH(CHF₂)₂, —CH(CF₃)₂, —CF(CH₃)₂, —CF₃.

“Haloalkoxy” is a haloalkyl group which is attached to another moietyvia an oxygen linker such as but are not limited to —OCHCF₂ or —OCF₃.

“Alkoxyalkyl” is an alkoxy group which is attached to another moiety viaan alkyl linker. “Hydroxyalkyl” or “dihydroxyalkyl” is one or twohydroxy groups, respectively, which are attached to another moiety viaan alkyl linker. Representative “hydroxyalkyl” or “dihydroxyalkyl”include —CH₂OH, —CH(OH)(CH₂)(OH), —C(OH)(CH₃)₂, —CH(OH)(CH₃),—CH(OH)(CH₂)(CH₃), —CH(OH)(CH₂)₂(CH₃), —C(CH₃)₂(OH), and the like.

“Cycloalkyl” means a non-aromatic monocyclic ring system of 3 to 10carbon atoms. In one embodiment, the cycloalkyl group has 3 to 6 carbonatoms. Exemplary cycloalkyl rings include cyclopropyl, cyclobutyl,cyclopentyl, and cyclohexyl.

“Cycloalkoxy” means a cycloalkyl group which is attached to anothermoiety via an oxygen linker (—O(cycloalkyl)).

“Monocyclic non-aromatic heterocycle” means a single saturatedheterocyclic ring, typically having 3- to 10-members and more typically3 to 7-members in the ring, wherein at least one atom in the ring is aheteroatom such as, for example, nitrogen, oxygen, sulfur, includingsulfoxide and sulfone. A 3- to 4-membered monocyclic non-aromaticheterocycle can contain up to 2 heteroatoms; a 5-6 membered monocyclicheterocycle can contain up to 3 heteroatoms and a 7- to 10-memberedmonocyclic non-aromatic heterocycle can contain up to 4 heteroatoms. Themonocyclic non-aromatic heterocycle may be attached to another group viaany heteroatom or carbon atom of the monocyclic non-aromaticheterocycle. Representative monocyclic non-aromatic heterocycles includemorpholinyl, thiomorpholinyl, pyrrolidinonyl, pyrrolidinyl, piperidinyl,piperazinyl, imidazolidinyl, pyrazolidinyl, oxazolidinyl,isothiazolidinyl, hydantoinyl, valerolactamyl, oxiranyl, oxetanyl,tetrahydrofuranyl, tetrahydropyranyl, tetrahydropyrindinyl,tetrahydropyrimidinyl, tetrahydrothiophenyl, tetrahydrothiopyranyl, andthe like. In one embodiment, a monocyclic non-aromatic heterocycle is aheterocyclic ring of 4, 5, 6, or 7 members.

“Monocyclic heteroaromatic” comprises carbon atom ring members and oneor more heteroatom ring members. Each heteroatom is independentlyselected from nitrogen, oxygen, and sulfur, including sulfoxide andsulfone. The point of attachment of a monocyclic heteroaromatic ring toanother group may be at either a carbon atom or a heteroatom of theheteroaromatic. In one embodiment, the monocyclic heteroaromatic ring isselected from 5 to 8 membered monocyclic heteroaromatic rings.Representative monocyclic heteroaromatic groups include pyridyl,1-oxo-pyridyl, furanyl, thienyl, pyrrolyl, oxazolyl, imidazolyl,thiazolyl, isoxazolyl, pyrazolyl, isothiazolyl, pyridazinyl,pyrimidinyl, pyrazinyl, a triazinyl, triazolyl, thiadiazolyl, andtetrazolyl.

C. Pharmaceutical Compositions, Formulations and Dosages

In one embodiment, provided herein is a pharmaceutical compositioncomprising a compound of the invention and a pharmaceutically acceptablecarrier or diluent.

In the pharmaceutical compositions of the invention, the compound of theinvention is present in an effective amount. The interrelationship ofdosages for animals and humans (based on milligrams per meter squared ofbody surface) is described in Freireich et al., Cancer Chemother. Rep,1966, 50: 219. Body surface area may be determined approximately fromheight and weight of the patient. See, e.g., Scientific Tables, GeigyPharmaceuticals, Ardsley, N.Y., 1970, 537.

The LXR modulators herein (e.g., compound(s) of the invention) can beformulated as pharmaceutical compositions and administered to a subject,such as a human, in a variety of forms adapted to the chosen route ofadministration. Typical routes of administering such pharmaceuticalcompositions include, without limitation, oral, topical, buccal,transdermal, inhalation, parenteral, sublingual, rectal, vaginal, andintranasal. The term parenteral as used herein includes subcutaneousinjections, intravenous, intramuscular, intrathecal, intrasternalinjection or infusion techniques. Methods of formulating pharmaceuticalcompositions are well known in the art, for example, as disclosed in“Remington: The Science and Practice of Pharmacy,” University of theSciences in Philadelphia, ed., 21st edition, 2005, Lippincott, Williams& Wilkins, Philadelphia, Pa. Each of the LXR modulators may be usedalone or in combination as a part of a pharmaceutical composition of theinvention.

The pharmaceutical compositions of the invention can be prepared bycombining a compound of the invention with an appropriatepharmaceutically acceptable carrier, diluent or excipient, and may beformulated into preparations in solid, semi-solid, liquid or gaseousforms, such as tablets, capsules, powders, granules, ointments,solutions, suppositories, injections, inhalants, gels, microspheres, andaerosols. Thus, the present compounds may be systemically administered,e.g., orally, in combination with a pharmaceutically acceptableexcipient such as an inert diluent or an assimilable edible carrier.They may be enclosed in hard or soft shell gelatin capsules, may becompressed into tablets or may be incorporated directly with the food ofthe patient's diet. For oral therapeutic administration, the activecompound may be combined with one or more excipients and used in theform of ingestible tablets, buccal tablets, troches, capsules, elixirs,suspensions, syrups, wafers, and the like.

Suitable tablets may be obtained, for example, by mixing one or morecompounds of the invention with known excipients, for example inertdiluents, carriers, disintegrants, adjuvants, surfactants, bindersand/or lubricants. The tablets may also consist of several layers.

The compounds of the invention can be suitably formulated intopharmaceutical compositions for administration to a subject. Thepharmaceutical compositions of the invention optionally include one ormore pharmaceutically acceptable carriers and/or diluents therefor, suchas lactose, starch, cellulose and dextrose. Other excipients, such asflavoring agents; sweeteners; and preservatives, such as methyl, ethyl,propyl and butyl parabens, can also be included. More complete listingsof suitable excipients can be found in the Handbook of PharmaceuticalExcipients (5th Ed., Pharmaceutical Press (2005)). A person skilled inthe art would know how to prepare formulations suitable for varioustypes of administration routes. Conventional procedures and ingredientsfor the selection and preparation of suitable formulations aredescribed, for example, in Remington's Pharmaceutical Sciences(2003-20th edition) and in The United States Pharmacopeia: The NationalFormulary (USP 24 NF19) published in 1999. The carriers, diluents and/orexcipients are “acceptable” in the sense of being compatible with theother ingredients of the pharmaceutical composition and not deleteriousto the recipient thereof.

Typically, for oral therapeutic administration, a compound of theinvention may be incorporated with excipient and used in the form ofingestible tablets, buccal tablets, troches, capsules, elixirs,suspensions, syrups, wafers, and the like.

Typically for parenteral administration, solutions of a compound of theinvention can generally be prepared in water suitably mixed with asurfactant such as hydroxypropylcellulose. Dispersions can also beprepared in glycerol, liquid polyethylene glycols, DMSO and mixturesthereof with or without alcohol, and in oils. Under ordinary conditionsof storage and use, these preparations contain a preservative to preventthe growth of microorganisms.

Typically, for injectable use, sterile aqueous solutions or dispersionof, and sterile powders of, a compound of the invention for theextemporaneous preparation of sterile injectable solutions ordispersions.

For nasal administration, the compounds of the invention can beformulated as aerosols, drops, gels and powders. Aerosol formulationstypically comprise a solution or fine suspension of the active substancein a physiologically acceptable aqueous or non-aqueous solvent and areusually presented in single or multidose quantities in sterile form in asealed container, which can take the form of a cartridge or refill foruse with an atomizing device. Alternatively, the sealed container may bea unitary dispensing device such as a single dose nasal inhaler or anaerosol dispenser fitted with a metering valve which is intended fordisposal after use. Where the dosage form comprises an aerosoldispenser, it will contain a propellant which can be a compressed gassuch as compressed air or an organic propellant such asfluorochlorohydrocarbon. The aerosol dosage forms can also take the formof a pump-atomizer

For buccal or sublingual administration, the compounds of the inventioncan be formulated with a carrier such as sugar, acacia, tragacanth, orgelatin and glycerine, as tablets, lozenges or pastilles.

For rectal administration, the compounds of the invention can beformulated in the form of suppositories containing a conventionalsuppository base such as cocoa butter.

Topical and/or local administration of the compounds of the inventioncan be achieved in a variety of ways including but not limited toointments, lotions, pastes, creams, gels, powders, drops, sprays,solutions, inhalants, patches, suppositories, retention enemas, chewableor suckable tablets or pellets and aerosols. Topical and/or localadministration may also involve the use of transdermal administrationsuch as transdermal patches or iontophoresis devices. For topical and/orlocal administration, the compounds of the invention can be formulatedas ointments, creams, milks, salves, powders, impregnated pads, syndets,solutions, gels, sprays, foams, suspensions, lotions, sticks, shampoosor washing bases. Compounds of the invention may also be administered inthe form of suspensions of lipid or polymer vesicles or nanospheres ormicrospheres or polymer patches and hydrogels for controlled release.

D. Methods of Treatment and Use of the LXR Modulators

Provided herein is a method of treating a subject with a disease ordisorder that is treatable by modulation of LXR. In one embodiment, LXRis modulated by upregulating LXR activity. The method comprisesadministering an effective amount of the compound of the invention.Moreover, provided herein is the use of a compound of the invention forthe manufacture of a medicament for treating a subject with a disease ordisorder that is treatable by upregulating LXR activity in a subject inneed thereof.

The methods provided herein may be useful for disorders treatable withLXR modulation, in particular LXR agonism.

Compounds of the invention are useful for the treatment or prevention ofdiseases or disorders associated with altered cholesterol transport,reverse cholesterol transport, fatty acid metabolism, cholesterolabsorption, cholesterol re-absorption, cholesterol secretion,cholesterol excretion, or cholesterol metabolism. Representativediseases or disorders include, but are not limited to, a lipid disorder;cancer, particularly hormone-dependent cancers, including ovarian,breast and prostate cancer; acneiform skin condition; skin inflammatorydisease; immunological disorder; condition characterized by a perturbedepidermal barrier function; condition of disturbed differentiation orexcess proliferation of the epidermis or mucous membrane; cardiovasculardisease; reproductive tract disorders; optic nerve and retinalpathology; degenerative neuropathy occurring in a disease; autoimmunedisease; traumatic damage to the central or peripheral nervous system;neurodegenerative disease; a degenerative process due to aging; diseasesor disorders of the kidney; and osteoporosis and related diseases.

In another embodiment, the disease or disorder is hyperlipidemia,hypercholesterolemia, hyperlipoproteinemia, hypertriglyceridemia,lipodystrophy, hepatic steatosis, nonalcoholic steatohepatitis (NASH),nonalcoholic fatty liver disease (NAFLD), hyperglycemia, insulinresistance, diabetes mellitus, dyslipidemia, atherosclerosis, gallstonedisease, acne vulgaris, dermatitis (including but not limited to,psoriasis, contact dermatitis, atopic dermatitis, and eczema), skinwounds, skin aging, photoaging, wrinkling, diabetes, Niemann-Pickdisease type C, Parkinson's disease, Alzheimer's disease, inflammation,xanthoma, obesity, metabolic syndrome, syndrome X, stroke, peripheralocclusive disease, memory loss, diabetic neuropathies, proteinuria,glomerulopathies (including but not limited to, diabetic nephropathy,hypertensive nephropathy, IGA nephropathy, focal segmentalglomerulosclerosis), hyperphosphatemia, cardiovascular complications ofhyperphosphatemia, cancer, multiple sclerosis, or osteoporosis.

In another embodiment, the disease or disorder is common acne;comedones; polymorphs; rosacea; nodulocystic acne; acne conglobate;senile acne; secondary acne, including but not limited to solar,medicinal and occupational acne; ichthyosis; ichthyosiform conditions;Darier's disease; palmoplantar keratoderma; leukoplakia; leukoplakiformconditions; cutaneous or mucous (oral) lichen; dermatological conditionsor afflictions with an inflammatory immunoallergic component, with orwithout a cellular proliferation disorder, including but not limited tocutaneous psoriasis, mucous psoriasis, ungual psoriasis, psoriaticrheumatism, cutaneous atopy, including eczema, respiratory atopy andgingival hypertrophy; benign or malignant dermal or epidermalproliferations, of viral or non-viral origin, including but not limitedto common warts, flat warts, epidermodysplasia verruciformis, oral orflorid papillomatoses, and T lymphoma or cutaneous T-cell lymphoma;proliferations that may be induced by ultraviolet light, including butnot limited to basocellular epithelioma and spinocellular epithelioma;precancerous skin lesions, including but not limited tokeratoacanthomas; immune dermatitides, including but not limited tolupus erythematosus; bullous immune diseases; collagen diseases,including but not limited to scleroderma; dermatological or systemicconditions or afflictions with an immunological component; skindisorders due to exposure to UV radiation; photo-induced orchronological aging of the skin; actinic pigmentations; keratosis;pathology associated with chronological or actinic aging, including butnot limited to xerosis; sebaceous function disorders, including but notlimited to hyperseborrhoea of acne, simple seborrhoea and seborrhoeicdermatitis; cicatrization disorders, including but not limited tostretch marks; pigmentation disorders, including but not limited tohyperpigmentation, melasma, hypopigmentation, and vitiligo; andalopecia, including but not limited to chemotherapy-associated alopeciaand radiation-associated alopecia.

In an embodiment, the disease or disorder is hypercholesterolemia,atherosclerosis or dyslipidemia. In another embodiment, the disease ordisorder is atherosclerosis or dyslipidemia. In yet another embodiment,the disease or disorder is atherosclerosis, Alzheimer's disease ordermatitis.

The present invention also provides a method for increasing reversecholesterol transport and/or for inhibiting the progression of orpromoting the regression of atherosclerosis.

The present invention also provides a method of treating diseases ordisorders associated with a need for increasing high density lipoprotein(HDL)-cholesterol levels comprising the administration of an effectiveamount of a compound of the invention to a mammal (particularly a human)in need thereof.

The present invention also provides a method of treating a disease ordisorder associated with a need for decreasing low density lipoprotein(LDL)-cholesterol levels comprising the administration of an effectiveamount of a compound of the invention to a mammal (particularly a human)in need thereof.

Additionally, provided herein is a method of increasing the expressionof an ATP-Binding Cassette protein in a subject's cells, therebyincreasing reverse cholesterol transport in a subject using thecompounds of the invention and compositions provided herein.

Standard physiological, pharmacological and biochemical procedures areknown to the art and are available for evaluating compounds of thepresent invention for the ability to modulate LXR activity. Such assaysinclude, for example, binding assays, fluorescence polarization assays,FRET based co-activator recruitment assays, and cell-basedco-transfection assays. Compounds of the present invention can beevaluated for their ability to modulate the expression of genes known tobe modulated by LXR. Established animal models can be used to study theprofiles of compounds of the present invention in relation to parametersdirectly relevant to diseases or disorders, including atherosclerosis,Alzheimer's disease, and skin conditions. Thus, compounds of the presentinvention can be tested in vivo in animal models by a variety of routesof administration, for example, oral gavage. Typically, in vivo compoundexposure can be examined in plasma and in tissues of interest. LXRactivity (as detected by gene expression of LXR-responsive genes) can beexamined in whole blood and tissues of interest. Lipids can bequantified in the plasma and the liver.

In particular, compounds of the present invention can be tested fortheir activity on ATP-Binding Cassette (ABC) cholesterol transporters,such as ABCA1 and ABCG1, and on lipogenic markers, such as SREBP1c atthe gene and protein expression level. The functional consequences ofABC transporter induction can be examined in cellular models forcholesterol efflux and in animal models for the reverse cholesterolpathway and atherosclerosis. Lipogenic markers can be examined in animalmodels by measuring plasma and liver triglyceride levels.

The compounds of the present invention can be used alone (i.e., as amonotherapy) or in combination with one or more other therapeutic agenteffective for treating any of the above indications. The pharmaceuticalcompositions can comprise the disclosed compounds alone as the onlypharmaceutically active agent or can comprise one or more additionalpharmaceutically active agents.

The present invention also provides combination therapy for treating orameliorating a disease or a disorder described herein. In someembodiments, the combination therapy comprises administering at leastone compound represented by Structural Formula I, II, III, IV, V, or VIin combination with one or more agents for treating or ameliorating adisease or a disorder described herein. In some embodiments, thecombination therapy comprises administering at least one compoundrepresented by Structural Formula I, II, III, IV, V, or VI incombination with one or more agents for the treatment of diseasesincluding hyperlipidemia, hypercholesterolemia, hyperlipoproteinemia,hypertriglyceridemia, lipodystrophy, hepatic steatosis, NASH, NAFLD,hyperglycemia, insulin resistance, diabetes mellitus, dyslipidemia,atherosclerosis, gallstone disease, acne vulgaris, dermatitis (includingbut not limited to, psoriasis, contact dermatitis, atopic dermatitis,and eczema), skin wounds, skin aging, photoaging, wrinkling, diabetes,Niemann-Pick disease type C, Parkinson's disease, Alzheimer's disease,inflammation, xanthoma, obesity, metabolic syndrome, syndrome X, stroke,peripheral occlusive disease, memory loss, diabetic neuropathies,proteinuria, glomerulopathies (including but not limited to, diabeticnephropathy, hypertensive nephropathy, IGA nephropathy, focal segmentalglomerulosclerosis), hyperphosphatemia, cardiovascular complications ofhyperphosphatemia, cancer, multiple sclerosis or osteoporosis.

In some embodiments, the compounds of the invention are used incombination with one or more additional agents for the treatment ofdiabetes, dyslipidemia, cardiovascular disease, hypertension, orobesity. Agents for the treatment of diabetes include insulins, such asHumulin® (Eli Lilly), Lantus® (Sanofi Aventis), Novolin® (Novo Nordisk),and Exubera® (Pfizer); PPAR gamma agonists, such as Avandia®(rosiglitizone maleate, GSK) and Actos® (pioglitazone hydrochloride,Takeda/Eli Lilly); sulfonylureas, such as Amaryl® (glimepiride, SanofiAventis), Diabeta®(glyburide, Sanofi Aventis), Micronase®/Glynase®(glyburide, Pfizer), and Glucotrol®/Glucotrol XL® and (glipizide,Pfizer); meglitinides, such as Prandin®/NovoNorm® (repaglinide, NovoNordisk), Starlix® (nateglinide, Novartis), and Glufast® (mitiglinide,Takeda); biguanides, such as Glucophage®/Glucophage XR® (metformin HCl,Bristol Myers Squibb) and Glumetza® (metformin HCl extended releasetablets, Depomed); thiazolidinediones; amylin analogs, GLP-1 analogs oragonists (including Byetta® (exenatide, Amylin/Eli Lilly) and Victoza®(recombinant liraglutide, Novo Nordisk)); DPP-IV inhibitors includingTradjenta™ (Eli Lilly/Boehringer Ingelheim), Januvia® (Merck), Galvus®(Novartis), and Onglyza® (Bristol-Myers Squibb/AstraZeneca); PTB-1 Binhibitors; protein kinase inhibitors (including AMP-activated proteinkinase inhibitors); glucagon antagonists, glycogen synthase kinase-3beta inhibitors; glucose-6-phoshatase inhibitors; glycogen phosphorylaseinhibitors; sodium glucose co-transporter inhibitors, andalpha-glucosidase inhibitors, such asPrecose®/Glucobay®/Prandase®/Glucor® (acarbose, Bayer) and Glyset®(miglitol, Pfizer). Agents for the treatment of dyslipidemia andcardiovascular disease include statins, fibrates, and ezetimbe. Agentsfor the treatment of hypertension include alpha-blockers, beta-blockers,calcium channel blockers, diuretics, angiotensin converting enzyme (ACE)inhibitors, dual ACE and neutral endopeptidase (NEP) inhibitors,angiotensin-receptor blockers (ARBs), aldosterone synthase inhibitors,aldosterone-receptor antagonists, or endothelin receptor antagonists.Agents for the treatment of obesity include orlistat, phentermine,sibutramine and rimonabant.

An embodiment of the invention includes administering an LXR modulatorcompound of the invention or composition thereof in a combinationtherapy with combination products, such as Avandamet® (metformin HCl androsiglitazone maleate, GSK); Avandaryl® (glimepiride and rosiglitazonemaleate, GSK); Metaglip® (glipizide and metformin HCl, Bristol MyersSquibb); and Glucovance® (glyburide and metformin HCl, Bristol MyersSquibb).

In some embodiments, the combination therapy comprises administering atleast one compound of the invention in combination with one or morecompound selected from the group of, for example, beta secretase (BACE1)inhibitors; gamma-secretase inhibitors; amyloid aggregation inhibitors(e.g., ELND-005); directly or indirectly acting neuroprotective and/ordisease-modifying substances; anti-oxidants (e.g., vitamin E orginkolide); anti-inflammatory substances (e.g., Cox inhibitors, NSAIDs);HMG-CoA reductase inhibitors (statins); acetylcholinesterase inhibitors(e.g., donepezil, rivastigmine, tacrine, galantamine, memantine;tacrine); NMDA receptor antagonists (e.g., memantine); AMPA receptoragonists; AMPA receptor positive modulators, AMPAkines, monoaminereceptor reuptake inhibitors, substances modulating the concentration orrelease of neurotransmitters; substances inducing the secretion ofgrowth hormone (e.g., ibutamoren mesylate and capromorelin); CB-1receptor antagonists or inverse agonists; antibiotics (e.g., minocyclinor rifampicin); PDE2, PDE4, PDE5, PDE9, PDE10 inhibitors, GABAA receptorinverse agonists, GABAA receptor antagonists, nicotinic receptoragonists or partial agonists or positive modulators, alpha4beta2nicotinic receptor agonists or partial agonists or positive modulators,alpha7 nicotinic receptor agonists or partial agonists or positivemodulators; histamine H3 antagonists, 5 HT-4 agonists or partialagonists, 5HT-6 antagonists, alpha2-adrenoreceptor antagonists, calciumantagonists, muscarinic receptor M1 agonists or partial agonists orpositive modulators, muscarinic receptor M2 antagonists, muscarinicreceptor M4 antagonists, metabotropic glutamate-receptor 5 positivemodulators, antidepressants, such as citalopram, fluoxetine, paroxetine,sertraline and trazodone; anxiolytics, such as lorazepam and oxazepam;antiphychotics, such as aripiprazole, clozapine, haloperidol,olanzapine, quetiapine, risperidone and ziprasidone, and othersubstances that modulate receptors or enzymes in a manner such that theefficacy and/or safety of the compounds according to the invention isincreased and/or unwanted side effects are reduced. The compoundsaccording to the invention may also be used in combination withimmunotherapies for the treatment of a disease or disorder disclosedherein.

Combination therapy includes co-administration of a compound of theinvention and one or more other agent, sequential administration of acompound of the invention and one or more other agent, administration ofa composition containing a compound of the invention and one or moreother agent, or simultaneous administration of separate compositionscontaining a compound of the invention and one or more other agent.

E. Exemplary Synthesis General Description of Synthetic Methods

The compounds of the present invention can be readily prepared accordingto the following reaction schemes and examples, or modificationsthereof, using readily available starting materials, reagents andconventional synthesis procedures. Many of the reactions can also becarried out under microwave conditions or using conventional heating orutilizing other technologies such as solid phase reagents/scavengers orflow chemistry. In these reactions, it is also possible to make use ofvariants which are themselves known to those of ordinary skill in thisart, but are not mentioned in greater detail. Furthermore, other methodsfor preparing compounds of the invention will be readily apparent to aperson of ordinary skill in the art in light of the following reactionschemes and examples. In cases where synthetic intermediates and finalproducts contain potentially reactive functional groups, for exampleamino, hydroxy, thiol and carboxylic acid groups, that may interferewith the desired reaction, it may be advantageous to employ protectedforms of the intermediate. Methods for the selection, introduction andsubsequent removal of protecting groups are well known to those skilledin the art. In the discussion below X, R¹, R², R³ and R⁴ have themeanings indicated above unless otherwise indicated. The abbreviationsused in these experimental details are listed below and additional onesshould be known to a person skilled in the art of synthesis. In additionone can refer to the following references for suitable methods ofsynthesis as described in March, Advanced Organic Chemistry, 3rdedition, John Wiley & Sons, 1985, Greene and Wuts, Protective Groups inOrganic Synthesis, 2^(nd) edition, John Wiley & Sons, 1991, and RichardLarock, Comprehensive Organic Transformations, 4^(th) edition, VCHpublishers Inc., 1989.

Generally, reagents in the reaction schemes are used in equimolaramounts; however, in certain cases it may be desirable to use an excessof one reagent to drive a reaction to completion. This is especially thecase when the excess reagent can be readily removed by evaporation orextraction. Bases employed to neutralize HCl in reaction mixtures aregenerally used in slight to substantial excess (1.05-5 equivalents).

Where NMR data are presented, spectra were obtained on a Varian 400 (400MHz) or 300 (300 MHz) and are reported as ppm downfield fromtetramethylsilane with number of proton, multiplicities and couplingconstants indicated parenthetically along with reference to deuteratedsolvent.

LC-MS data were obtained by utilizing one or more of the followingchromatographic conditions:

Method 1 (10-80, 2 min)

Column Xtimate ™ C18 2.1 * 30 mm, 3 μm Mobile Phase A: water (4 L) + TFA(1.5 mL) B: acetonitrile (4 L) + TFA (0.75 mL) TIME (min) A % B % 0 9010 0.9 20 80 1.5 20 80 1.51 90 10 2 90 10 Flow Rate 1.2 mL/minwavelength UV 220 nm Oven Temp 50° C. MS ionization ESIMethod 2 (30-90, 2 min)

Column Xtimate ™ C18 2.1 * 30 mm, 3 μm Mobile Phase A: water (4 L) + TFA(1.5 mL) B: acetonitrile (4 L) + TFA (0.75 mL) TIME (min) A % B % 0 7030 0.9 10 90 1.5 10 90 1.51 70 30 2 70 30 Flow Rate 1.2 mL/minwavelength UV 220 nm Oven Temp 50° C. MS ionization ESIMethod 3 (0-60, 2 min)

Column Xtimate ™ C18 2.1 * 30 mm, 3 μm Mobile Phase A: water (4 L) + TFA(1.5 mL) B: acetonitrile (4 L) + TFA (0.75 mL) TIME (min) A % B % 0 1000 0.9 40 60 1.5 40 60 1.51 100 0 2 100 0 Flow Rate 1.2 mL/min wavelengthUV 220 nm Oven Temp 50° C. MS ionization ESI

Method 4:

-   -   HPLC System: Waters ACQUITY; Column: Waters ACQUITY CSH™ C18 1.7        μM Guard column: Waters Assy. Frit, 0.2 μM, 2.1 mm; Column tem:        40° C. Mobile Phase: A: TFA: Water (1:1000, v:v) Mobile phase B:        TFA: ACN (1:1000, v:v); Flow Rate: 0.65 mL/min; Injection        Volume: 2 μL; Acquisition time: approximately 1.5 minute.

Gradient Program: Time (min) B % 0 10 0.8 90 1.20 90 1.21 10

Mass Spectrometer Parameters

Mass Spectrometer: Waters SQD; Ionization: Positive ElectrosprayIonization (ESI); Mode Scan (100-1400 m/z in every 0.2 second); ESCapillary Voltage: 3.5 kv; ES Cone Voltage: 25 v Source Temperature:120° C.; Disolvation Temperature: 500° C.; Desolvation Gas Flow:Nitrogen Setting 650 (L/hr); Cone Gas Flow: Nitrogen Setting 50 (L/hr).

SFC separation of compounds of the invention were carried out under thefollowing methods.

Method A:

-   -   Instrument: Thar SFC 80; Column: AD 250 mm*30 mm, 5 μm; Mobile        phase: A: Supercritical CO₂, B: IPA (0.05% DEA), A: B=80:20 at        60 ml/min; Column Temp: 38° C.; Nozzle Pressure: 100 Bar; Nozzle        Temp: 60° C.; Evaporator Temp: 20° C.; Trimmer Temp: 25° C.;        Wavelength: 220 nm.

Method B:

-   -   Instrument: SFC MG2; Column: OJ 250 mm*30 mm, 5 μm; Mobile        phase: A: Supercritical CO₂, B: MeOH (0.05% DEA), A:B=90:10 at        70 ml/min; Column Temp: 38° C.; Nozzle Pressure: 100 Bar Nozzle        Temp: 60° C.; Evaporator Temp: 20° C.; Trimmer Temp: 25° C.;        Wavelength: 220 nm.

The chiral purity of compounds of the invention was determined byanalytical chiral HPLC, which was carried out using Chiralcel® orChiralpak® columns, using CO₂, together with from 5% to 40% methanol,ethanol or isopropanol, containing 0.05% DEA as eluents.

Analytical Chiral HPLC

Method Detailed information OJ-H_3_5_40_2.35ML Column: Chiralcel ® OJ-H250 × 4.6 mm I.D., 5 μm Mobile phase: methanol (0.05% DEA) in CO₂ from5% to 40% Flow rate: 2.35 mL/min Wavelength: 220 nm OJ-H_3_5_40_2.5MLColumn: Chiralcel ® OJ-H 250 × 4.6 mm I.D., 5 μm Mobile phase: methanol(0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.5 mL/min Wavelength: 220nm AS-H_3_5_40_2.35ML Column: Chiralpak ® AS-H 250 × 4.6 mm I.D., 5 μmMobile phase: methanol (0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.35mL/min Wavelength: 220 nm AS-H_4_5_40_2.5ML Column: Chiralpak ® AS-H 250× 4.6 mm I.D., 5 μm Mobile phase: iso-propanol (0.05% DEA) in CO2 from5% to 40% Flow rate: 2.5 mL/min Wavelength: 220 nm AS-H_5_5_40_2.35MLColumn: Chiralpak ® AS-H 250 × 4.6 mm I.D., 5 μm Mobile phase: ethanol(0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.35 mL/min Wavelength: 220nm AS-H_3_5_40_2.5ML Column: Chiralpak ® AS-H 250 × 4.6 mm I.D., 5 μmMobile phase: methanol (0.05% DEA) in CO2 from 5% to 40% Flow rate: 2.5mL/min Wavelength: 220 nm AD-H_3_5_40_2.35ML Column: Chiralpak ® AD-H250 × 4.6 mm I.D., 5 μm Mobile phase: methanol (0.05% DEA) in CO₂ from5% to 40% Flow rate: 2.35 mL/min Wavelength: 220 nm AD-H_5_5_40_2.35MLColumn: Chiralpak ® AD-H 250 × 4.6 mm I.D., 5 μm Mobile phase: ethanol(0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.35 mL/min Wavelength: 220nm OD-3_3_5_40_2.5ML Column: Chiralcel ® OD-3 150 × 4.6 mm I.D., 3 μmMobile phase: methanol (0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.5mL/min Wavelength: 220 nm OD-3_4_5_40_2.5ML Column: Chiralcel ® OD-3 150× 4.6 mm I.D., 3 μm Mobile phase: iso-propanol (0.05% DEA) in CO₂ from5% to 40% Flow rate: 2.5 mL/min Wavelength: 220 nm OD-3_5_5_40_2.5MLColumn: Chiralcel ® OD-3 150 × 4.6 mm I.D., 3 μm Mobile phase: ethanol(0.05% DEA) in CO₂ from 5% to 40% Flow rate. 2.5 mL/min Wavelength: 220nm AD-3_3_5_40_2.5ML Column: Chiralpak ® AD-3 150 × 4.6 mm I.D., 3 μmMobile phase: methanol (0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.5mL/min Wavelength: 220 nm AD-3_4_5_40_2.5ML Column: Chiralpak ® AD-3 150× 4.6 mm I.D., 3 μm Mobile phase: iso- propanol (0.05% DEA) in CO₂ from5% to 40% Flow rate: 2.5 mL/min Wavelength: 220 nm AD-3_5_5_40_2.5MLColumn: Chiralpak ® AD-3 150 × 4.6 mm I.D., 3 μm Mobile phase: ethanol(0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.5 mL/min Wavelength: 220nm OD-H_3_5_40_2.35ML Column: Chiralcel ® OD-H 250 × 4.6 mm I.D., 5 μmMobile phase: methanol (0.05% DEA) in CO₂ from 5% to 40% Flow rate: 2.35mL/min Wavelength: 220 nm OD-H_5_5_40_2.35ML Column: Chiralcel ® OD-H250 × 4.6 mm I.D., 5 μm Mobile phase: ethanol (0.05% DEA) in CO₂ from 5%to 40% Flow rate: 2.35 mL/min Wavelength: 220 nm

The invention is illustrated by way of the following examples, in whichthe following abbreviations may be employed:

Abbreviation Meaning ACN, MeCN, CH₃CN acetonitrile Aq aqueous Boctert-butoxy carbonyl or t-butoxy carbonyl brine saturated aqueous NaClCbz benzyloxy carbonyl CeCl₃ ceric chloride Cs₂CO₃ cesium carbonate CuIcuprous iodide DCM or CH₂Cl₂ methylene chloride DIEA diisopropyl ethylamine DMF dimethyl formamide DMS/Me2S dimethyl sulfide DMSO dimethylsulfoxide EDCI 1-(3-dimethylaminopropyl)-3-ethylcarbodiiimidehydrochloride EtI ethyl iodide Et ethyl Et₂O ethyl ether Et₃SiHtriethylsilane Et₃N triethylamine EtOAc, EA, AcOEt ethyl acetate EtOHethanol FeCl₃ ferric chloride h, hr hour(s) HATUO-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium-hexafluorophosphate HBTUO-Benzotriazole-1-yl-N,N,N′,N′- tetramethyluronium-hexafluorophosphateHCl hydrochloric acid H₂O water H₂O₂ hydrogen peroxide HPLC highperformance liquid chromatography i-BuOCOCl iso-butoxycarbonyl chlorideICl iodochloride K₂CO₃ potassium carbonate K₃PO₄ tripotassium phosphateLC-MS liquid chromatography-mass spectrometry LDA lithiumdiiisopropylamide LiCl lithium chloride LiOH lithium hydroxide MCPBA,m-CPBA meta-chloroperoxybenzoic acid MeOH methanol MeI methyl iodide Memethyl mg milligram Mg₂SO₄ magnesium sulfate (anhydrous) min minute(s)mL milliliters mmol millimoles mp, m.p. melting point MS massspectrometry MW microwave NaBH₄ sodium borohydride NaBH₃CN sodiumcyanoborohydride NaH sodium hydride NaHCO₃ sodium bicarbonate NaOHsodium hydroxide NaOMe sodium methoxide Na₂S₂O₃ sodium thiosulfateNa₂S₂O₅ sodium dithionate Na₂SO₄ sodium sulfate NH₄OH ammonium hydroxide(NH₄)₂CO₃ ammonium carbonate NH₄Cl ammonium chloride Na₂CO₃ sodiumcarbonate NaHCO₃ sodium bicarbonate NaH sodium hydride n-BuLin-butyllithium NMM N-methyl-morpholine NMP N-methyl-pyrrolidin-2-one OTftrifluoromethanesulfonate OTs tosylate PdCl₂dppf[1,1-bis(diphenylphosphino)ferrocene] dichloropalladium(ii) Pd₂(dba)₃tris(dibenzylideneacetone)dipalladium(0) PE petroleum ether rt roomtemperature sat. saturated SFC supercritical fluid chromatography t-BuOKpotassium tert butoxide t-BuLi tert butyl lithium t-BuOOH tert butylperoxide TBAF tetrabutylammonium fluoride TFA trifluoroacetic acid THFtetrahydrofuran TLC thin layer chromatography Ti(OEt)₄ titanium tetraethoxide Zn zinc Zn(CN)₂ zinc cyanide

In the first process, a compound of Formula I can be prepared by S_(N)Aror palladium catalyzed reactions of reagents of 1, where G¹ is Cl, Br,I, OTf or OTs, with intermediates of Formula 2. Reagents 1 are eithercommercially available or can be prepared readily from commerciallyavailable precursors based on literature precedents.

Intermediates 2 can be prepared by one of the several different methodsdepicted below.

When X═N, intermediates of Formula 2 can be prepared by cyclization ofintermediates of Formula 3a followed by removal of G² when G² is nothydrogen. G² is an amine protecting group, such as Boc, Cbz andtrifluoroacetamide, etc.

Intermediates of Formula 3a can be prepared by one of the twomethods: 1) copper mediated coupling of piperazinone 4a and aniline 5a,where G³ is Br, I, Cl or OTf; 2) S_(N)Ar reaction between 4a andfluorinated nitrobenzene 6a to give intermediate of Formula 7a followedby reduction of the nitro group. The intermediate 7a can also beprepared from an intermediate of Formula 8a by displacement of fluorinewith either sodium alkanesulfinate (R¹SO₂Na) or sodium alkylsulfide(R¹SNa) followed by oxidation of the resulting thioether. Theintermediate 8a in turn can be prepared from piperazinone 4a anddifluoro nitrobenzene 9a, which are either commercially available or canbe readily prepared from commercial precursors based on literatureprocedures, well known to those of ordinary skill in the art.

For example, when R³=isopropyl, piperazinone 4a can be prepared by oneof the methods presented below.

When X═CH, intermediates of Formula 2 can be prepared from intermediatesof Formula 3b by deprotection of G² followed by reductive amination. G²are amine protecting groups, such as Boc, Cbz and trifluoroacetamideetc.

Intermediates of Formula 3b can be prepared by N-alkylation of indole 4bwith commercially available alkyl halide 5b, where G³ is Br or I.Intermediates of Formula 4b can be prepared by removal of G⁴ fromintermediates of Formula 6b, where G⁴ is methanesulfonate orphenylsulfonate.

Intermediates of Formula 6b can be prepared by sequential Sonogashiracoupling reaction between aryl halides 7b (where G⁵ is Br or I) andpropargyl alcohols 8b, followed by cyclization, to give intermediates ofFormula 9b, followed by oxidation of the alcohol.

Intermediates of Formula 7b can be prepared from commercially availableaniline 10b via the following transformations: 1) Displacement offluorine with sodium alkyl sulfide R¹SNa (yielding 11b); 2) Halogenation(yielding 12b); 3) Protection of aniline (yielding 13b); 4) Oxidation ofsulfide (yielding 7b).

In the second process, a compound of Formula I, where R¹=alkyl, R²═H andX═CH, can be prepared by oxidation of the thioether group inintermediates of Formula 1c. Intermediate 1c in turn can be preparedfrom coupling of reagents 1 and intermediates of Formula 2c via S_(N)Aror palladium catalyzed reactions.

Intermediates 2c can be prepared according to following scheme.

All patents, patent applications, books and literature cited in thespecification are hereby incorporated by reference in their entirety. Inthe case of any inconsistencies, the present disclosure, including anydefinitions therein will prevail.

The invention will be further described by reference to the followingdetailed examples, which are given for illustration of the invention,and are not intended to be limiting thereof.

Example 11-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine

Step 1:

To a solution of (R)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoicacid (2.0 g, 9.20 mmol) in CH₂Cl₂ (40 mL) were added2-(benzylamino)ethanol (1.3 g, 8.80 mmol), HATU (5.30 g, 13.8 mmol) andEt₃N (2.80 g, 27.6 mmol) under N₂. The mixture was stirred at rtovernight. The mixture was added water (20 mL) and extracted with EtOAc(3×30 mL). The combined organic layers were washed with brine (20 mL),dried over anhydrous Na₂SO₄, filtered, concentrated and then purified bycolumn chromatography on silica gel to afford (R)-tert-butyl(1-(benzyl(2-hydroxyethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate(2.80 g, 88% yield) as a white solid. LC-MS m/z 351.2 [M+H]⁺.

Step 2:

To a solution of (R)-tert-butyl(1-(benzyl(2-hydroxyethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate(2.80 g, 8.0 mmol) in CH₂Cl₂ (20 mL) was added Et₃N (1.60 g, 16 mmol)and MsCl (1.40 g, 12.0 mmol) dropwse at −10° C. under N₂. The mixturewas stirred at rt overnight. The mixture was quenched with water (20 mL)and extracted with CH₂Cl₂ (3×20 mL). The combined organic layers werewashed with brine (20 mL) and dried over anhydrous Na₂SO₄, filtered,concentrated to afford (R)-tert-butyl(1-(benzyl(2-chloroethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate (3.0g, 100% yield) as a yellow solid, which was used for the next stepwithout further purification. LC-MS m/z 369.2 [M+H]⁺. ¹H NMR (CDCl₃ 400MHz): δ 7.37-7.28 (m, 3H), 7.22-7.20 (m, 2H), 5.27-5.18 (m, 1H),4.93-4.86 (m, 1H), 4.64-4.39 (m, 2H), 3.85-3.66 (m, 2H), 3.61-3.39 (m,2H), 2.03-1.97 (m, 1H), 1.45 (s, 9H), 0.98 (d, J=6.8 Hz, 3H), 0.93 (d,J=6.8 Hz, 3H).

Step 3:

To a solution of (R)-tert-butyl(1-(benzyl(2-chloroethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate (2.0g, 5.40 mmol) in DMF (30 mL) was added NaH (1.0 g, 27.0 mmol, 60% inmineral oil) at 0° C. under N₂. The mixture was stirred at rt for 2 h.The mixture was quenched with water (20 mL) and extracted with EtOAc(3×20 mL). The combined organic layers were washed with brine (20 mL)and dried over anhydrous Na₂SO₄, filtered, concentrated and purified bycolumn chromatography to afford (R)-tert-butyl4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate (1.13 g, 63% yield)as a white solid. LC-MS m/z 277.1 [M-56+H]⁺. ¹H NMR (CDCl₃ 400 MHz): δ7.38-7.29 (m, 3H), 7.29-7.22 (m, 2H), 5.02-4.86 (m, 1H), 4.49-4.39 (m,1H), 4.31-4.06 (m, 2H), 3.41-3.18 (m, 3H), 2.42-2.31 (m, 1H), 1.46 (s,9H), 1.12 (d, J=6.8 Hz, 3H), 1.00 (d, J=6.8 Hz, 3H).

Step 4:

To a three-necked bottle containing THF (10 mL) was bubbled with NH₃(gas) at −78° C. for 5 mins. Then Na (300 mg, 13.0 mmol) was added tothe mixture slowly at −78° C. After stirring for 30 min, (R)-tert-butyl4-benzyl-2-isopropyl-3-oxopiperazine-1-carboxylate (700 mg, 2.11 mmol)was added dropwise at −78° C. The mixture was stirred at −78° C. for 30min. The mixture was quenched with sat. aq. NH₄Cl (10 mL) and extractedwith EtOAc (3×10 mL). The combined organic layers were washed with brine(10 mL), dried over anhydrous Na₂SO₄, filtered, concentrated andpurified by preparative TLC with petroleum ether/EtOAc 1/1 to affordtert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate (300 mg, 59% yield)as a white solid. The product was found to be a racemic mixture. Thecause of racemization was not investigated. LC-MS m/z 187.1 [M-56+H]⁺,265.1 [M+Na]⁺. ¹H NMR (CDCl₃ 400 MHz): δ 6.29 (s, 1H), 4.55-3.99 (m,2H), 3.51-3.36 (m, 1H), 3.32-3.12 (m, 2H), 2.34-2.29 (m, 1H), 1.46 (s,9H), 1.09 (d, J=6.8 Hz, 3H), 0.99 (d, J=7.2 Hz, 3H).

Step 5:

To a solution of tert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate(200 mg, 0.83 mmol) in NMP (3 mL) were added2-bromo-4-(methylsulfonyl)aniline (207 mg, 0.83 mmol),(1R,2S)—N1,N2-dimethylcyclohexane-1,2-diamine (12.0 mg, 0.08 mmol),K₃PO₄.3H₂O (660 mg, 2.48 mmol) and Cul (16 mg, 0.08 mmol). The mixturewas stirred at 150° C. for 1 h in a microwave oven. The mixture wasdiluted with water (10 mL) and extracted with EtOAc (3×10 mL). Thecombined organic layers were washed with brine (10 mL), dried overanhydrous Na₂SO₄, filtered, concentrated and purified by preparative TLCwith CH₂Cl₂/MeOH 35/1 to afford tert-butyl1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate(110 mg, 34% yield) as a white solid. LC-MS m/z 394.1 [M+H]⁺. ¹H NMR(CDCl₃ 400 MHz): δ 7.94 (s, 1H), 7.83-7.76 (m, 2H), 5.35-5.17 (m, 1H),4.73-4.42 (m, 1H), 4.22-4.12 (m, 1H), 4.11-3.99 (m, 1H), 3.53-3.37 (m,1H), 3.03 (s, 3H), 2.38-2.27 (m, 1H), 1.42 (s, 9H), 1.19 (d, J=6.8 Hz,3H), 0.97 (d, J=6.8 Hz, 3H).

Step 6:

To a solution of tert-butyl1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2(1H)-carboxylate(20 mg, 0.05 mmol) in CH₂Cl₂ (1 mL) was added TFA (0.3 mL) under N₂. Themixture was stirred at rt for 1 h. The mixture was concentrated toafford1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine(20 mg, TFA salt, 100% yield) as a yellow solid, which was used for thenext step without further purification. LC-MS m/z 352.1 [M+H]⁺.

Step 7:

To a solution of1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine(15 mg, 0.05 mmol) in DMSO (3 mL) was added2-chloro-4-(trifluoromethyl)pyrimidine (19 mg, 0.10 mmol) and DIEA (20mg, 0.15 mmol) under N₂. The mixture was stirred at 100° C. for 2 h.Water (10 mL) was added and the mixture was extracted with EtOAc (3×10mL). The combined organic layers were washed with brine (10 mL), driedover anhydrous Na₂SO₄, filtered, concentrated and then purified bypreparative TLC to afford1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine(5.10 mg, 23% yield) as a white solid. LC-MS m/z 440.2 (MH⁺). ¹H NMR(CDCl₃ 400 MHz): δ 8.58 (d, J=4.8 Hz, 1H), 8.01 (d, J=0.8 Hz, 1H),7.90-7.81 (m, 2H), 6.89 (d, J=4.8 Hz, 1H), 6.12 (d, J=8.0 Hz, 1H), 5.39(dd, J=4.0 and 14.0 Hz, 1H), 4.34-4.30 (m, 1H), 4.23-4.16 (m, 1H),3.83-3.75 (m, 1H), 3.09 (s, 3H), 2.55-2.49 (m, 1H), 1.33 (d, J=6.8 Hz,3H), 1.09 (d, J=6.8 Hz, 3H).

Example 2(R)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanoland(S)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol

Racemization Occurred During the Course of Synthesis Step 1:

A solution of Cbz-D-Valine (500 g, 1.99 mol) and N-methylmorpholine(201.8 g, 1.99 mol) in anhydrous THF (8 L) was cooled to −15° C. andi-butyl chlorofomate (299 g, 2.19 mol) was added dropwise understirring. After 30 min, a solution of 1-amino-2,2-dimethyoxyethane(209.5 g, 1.99 mol) in THF (1 L) was added slowly and the temperaturewas maintained at −15° C. for 2 h. The reaction mixture was washed withbrine (2 L) and the organic phase was concentrated to remove the THF.The residue was diluted with EtOAc (4 L), washed with 1N aq HCl (2×2 L),sat. aq. NaHCO₃ (2 L) and sat. aq. Na₂CO₃ (2 L) and brine (1.5 L). Afterdrying over Na₂SO₄, the organic solvent was removed under reducepressure to afford (R)-benzyl(1-((2,2-dimethoxyethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate as awhite solid (670 g, yield 99.5%), which was used for next step withoutfurther purification. LC-MS m/z 360.9 [M+Na]⁺.

¹H NMR (CD₃OD 300 MHz): δ 7.35-7.30 (m, 5H), 5.08 (s, 2H), 4.45-4.35 (m,1H), 3.95-3.85 (m, 1H), 3.34-3.25 (m, 8H), 2.10-1.90 (m, 1H), 0.94-0.91(m, 6H).

Step 2:

(R)-benzyl(1-((2,2-dimethoxyethyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate (335g, 0.99 mol) was added in portions to a cooled TFA-H₂O (temperature <5°C., V_(TFA)/V_(H2O)=7/3, 2 L), and the solution was stirred at rt for 12h. The solution was added slowly into stirring cooled sat. aq. Na₂CO₃(2.5 L) to keep the pH>8. The mixture was extracted with EtOAc (5×2 L).The combined organic layers were washed with brine (2 L), dried overanhydrous Na₂SO₄, filtered and evaporated in vacuo to give (R)-benzyl2-isopropyl-3-oxo-3,4-dihydropyrazine-1(2H)-carboxylate as a white solid(259 g, 95.4%), which was used for next step without furtherpurification. LC-MS m/z 274.9 [M+H]⁺. ¹H NMR (CD₃OD 300 MHz): δ7.36-7.34(m, 5H), 6.33-6.30 (m, 1H), 5.79-5.68 (m, 1H), 5.26-5.13 (m, 2H),4.38-4.29 (m, 1H), 2.01-1.96 (m, 1H), 1.00-0.84 (m, 6H).

Step 3:

To a stirring solution of (R)-benzyl2-isopropyl-3-oxo-3,4-dihydropyrazine-1(2H)-carboxylate (400 g, 1.46mol) in DCE (2 L) was added Et₃SiH (424 g, 3.65 mol) and TFA (665 g, 5.8mol) at rt. The reaction was stirred under reflux for 36 h. Aftercooling to rt, the solution was concentrated to remove the solvent. Theresidue was diluted with EtOAc (2 L), and added slowly into stirringcooled sat. aq. NaHCO₃ (2 L) to make sure that the pH>8. The mixture wasextracted with EtOAc (2×2.5 L). The combined organic layers were washedwith brine, dried over anhydrous Na₂SO₄, filtered and concentrated togive (R)-benzyl 2-isopropyl-3-oxopiperazine-1-carboxylate (402 g, yield99.75%), which was used for next step without further purification.LC-MS m/z 276.9 [M+H]⁺. ¹H NMR (DMSO-d₆ 400 MHz): δ 7.93 (s, 1H),7.39-7.31 (m, 5H), 5.09 (s, 2H), 4.06-4.01 (m, 1H), 3.99-3.92 (m, 1H),3.23-3.14 (m, 3H), 2.20-2.12 (m, 1H), 0.96-0.94 (m, 3H), 0.85 (d, J=6.0Hz, 3H).

Step 4:

To a 1 L round-bottom flask containing (R)-benzyl2-isopropyl-3-oxopiperazine-1-carboxylate (50 g, 0.181 mol) in MeOH (800mL) was added Pd/C (dry, w/w 15%, 5 g). The mixture was stirred at rtunder H₂ (1 atm) overnight. When TLC and LC-MS showed that the startingmaterial was consumed, (Boc)₂O (76.74 g, 0.352 mol) was added to thereaction mixture, and the mixture was stirred at rt overnight until theintermediate (R)-3-isopropylpiperazin-2-one was consumed. The mixturewas filtered and concentrated under vacuum. The residue was purified bycolumn chromatography on silica gel (eluting with petroleum: EtOAc=3:1)to give (R)-tert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate as awhite solid (26 g, yield 61%).

For (R)-3-isopropyl-piperazin-2-one:

LC-MS m/z 143.2 [M+H]⁺. ¹H NMR (HCl salt, CD₃OD 400 MHz): δ 3.95 (d,J=3.6 Hz, 1H), 3.65-3.39 (m, 4H), 2.63-2.54 (m, 1H), 1.15 (d, J=6.8 Hz,3H), 1.09 (d, J=7.2 Hz, 3H).

For (R)-tert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate:

LC-MS m/z 186.9 [M-56+H]⁺. ¹H NMR (DMSO-d₆ 400 MHz): δ 7.93 (s, 1H),4.02-3.82 (m, 2H), 3.17-3.15 (m, 3H), 2.16 (s, 1H), 1.41 (s, 9H), 0.98(d, J=6.8 Hz, 3H), 0.89 (d, J=6.4 Hz, 3H).

Step 5:

Under N₂ atmosphere, NaH (8.8 g, 0.22 mol, 60% in mineral oil, 1.1 eq.)was added in portions at −10° C. to a 1 L three-neck flask containing(R)-tert-butyl 2-isopropyl-3-oxopiperazine-1-carboxylate (26.66 g, 0.11mol) in DMF (300 mL). The mixture was stirred at −10° C. for 30 min.Then the mixture was added dropwise to a 1 L three-neck flask containingmethyl 2,4-difluoro-5-nitrobenzoate (26.3 g, 0.121 mol, 1.1 eq.) in DMF(200 mL) at −20° C. over 10 min After addition, the resulting mixturewas stirred between −20° C. and −30° C. for another 10 min. The reactionwas quenched with sat. aq. NH₄Cl (200 mL) and then water (800 mL). Theaqueous layer was extracted with EtOAc (3×1 L). The combined organiclayers were washed with water (3×1 L) and brine, and dried overanhydrous Na₂SO₄. The mixture was filtered and the filtrate wasevaporated under vacuum. The residue was purified by columnchromatography on silica gel eluting with petroleum ether: EtOAc 8:1˜4:1to give (R)-tert-butyl4-(5-fluoro-4-(methoxycarbonyl)-2-nitrophenyl)-2-isopropyl-3-oxopiperazine-1-carboxylate(32 g, 66.3% yield) as a yellow solid. LC-MS MS (ESI) m/z 384.1[M-56+H]⁺, 462.1 [M+Na]⁺. ¹H NMR (CDCl₃ 300 MHz): δ 8.63 (d, J=6.9 Hz,1H), 7.16 (d, J=10.2 Hz, 1H), 4.61-4.30 (m, 2H), 3.97-3.89 (m, 4H),3.62-3.48 (m, 2H), 2.40-2.34 (m, 1H), 1.49 (s, 9H), 1.08 (d, J=6.9 Hz,3H), 1.01 (d, J=6.9 Hz, 3H).

Step 6:

To a 1 L round-bottom flask containing (R)-tert-butyl4-(5-fluoro-4-(methoxycarbonyl)-2-nitrophenyl)-2-isopropyl-3-oxopiperazine-1-carboxylatewas added NaSMe (14.3 g, 0.204 mmol, 3 eq.). The mixture was stirred atrt for 1 h. Water (500 mL) was added and the mixture was concentratedunder vacuum to remove THF. The aqueous layer was extracted with EtOAc(3×800 mL). The combined organic layers were washed with brine, driedover anhydrous Na₂SO₄, filtered and concentrated under vacuum to give(R)-tert-butyl2-isopropyl-4-(4-(methoxycarbonyl)-5-(methylthio)-2-nitrophenyl)-3-oxopiperazine-1-carboxylate(31.9 g, 100% yield) as a yellow solid. The residue was used directlyfor the next step without further purification. LC-MS MS (ESI) m/z 412.1[M-56+H]⁺, 490.2 [M+Na]⁺.

Step 7:

To a 2 L round-bottom flask containing (R)-tert-butyl2-isopropyl-4-(4-(methoxycarbonyl)-5-(methylthio)-2-nitrophenyl)-3-oxopiperazine-1-carboxylate(crude 91.7 g, 0.196 mol) in CH₂Cl₂ (1 L) was added m-CPBA (84.6 g, 0.49mmol, 2.5 eq). The mixture was stirred at rt overnight. Sat. Na₂S₂O₃solution was added slowly to quench the reaction. The mixture wasextracted with CH₂Cl₂ (4×3 L). The combined organic layers were washedsuccessively with Na₂S₂O₃ solution (500 mL), NaHCO₃ solution (500 mL)and brine, dried over anhydrous Na₂SO₄, filtered and concentrated undervacuum. The residue was purified by column chromatography on silica geleluting with dichloromethane to give (R)-tert-butyl2-isopropyl-4-(4-(methoxycarbonyl)-5-(methylsulfonyl)-2-nitrophenyl)-3-oxopiperazine-1-carboxylate(83.7 g, 85.4% yield) as a yellow solid. LC-MS MS (ESI) m/z 444.0[M-56+H]⁺, 522.1 [M+Na]⁺. ¹H NMR (CDCl₃ 300 MHz): δ 8.29 (s, 1H), 8.12(s, 1H), 4.61-4.17 (m, 2H), 4.00-3.94 (m, 4H), 3.70-3.60 (m, 1H),3.51-3.43 (m, 4H), 2.39-2.32 (m, 1H), 1.50 (s, 9H), 1.07 (d, J=6.9 Hz,3H), 1.01 (d, J=6.9 Hz, 3H).

Step 8:

To a 1 L round-bottom flask containing (R)-tert-butyl2-isopropyl-4-(4-(methoxycarbonyl)-5-(methylsulfonyl)-2-nitrophenyl)-3-oxopiperazine-1-carboxylate(26.3 g, 0.0526 mol) in THF (200 mL) and methanol (200 mL) was addedRaney Nickel (in H₂O, 4 g). The mixture was stirred under H₂ (30 psi) atrt overnight. The mixture was filtered and concentrated under vacuum togive (R)-tert-butyl4-(2-amino-4-(methoxycarbonyl)-5-(methylsulfonyl)phenyl)-2-isopropyl-3-oxopiperazine-1-carboxylate(24.7 g, 100% yield) as a yellow solid. The residue was used directlyfor the next step without further purification.

LC-MS MS (ESI) m/z 414.0 [M-56+H]⁺, 492.0 [M+Na]⁺. ¹H NMR (CDCl₃ 300MHz): δ 7.77 (brs, 1H), 7.04 (s, 1H), 4.68-4.45 (m, 1H), 4.45-4.38 (m,2H), 3.92 (s, 3H), 3.70-3.58 (m, 1H), 3.58-3.41 (m, 1H), 3.30 (s, 3H),2.49-2.25 (m, 1H), 1.50 (s, 9H), 1.12 (d, J=6.9 Hz, 3H), 1.05 (d, J=6.9Hz, 3H).

Step 9:

To a 1 L round-bottom flask containing (R)-tert-butyl4-(2-amino-4-(methoxycarbonyl)-5-(methylsulfonyl)phenyl)-2-isopropyl-3-oxopiperazine-1-carboxylate(25 g, 0.0532 mol) in dichloromethane (500 mL) were added Et₃N (64.5 g,0.638 mol, 12 eq.) and SiCl₄ (27.1 g, 0.160 mol, 3 eq.). The mixture wasstirred at rt overnight. The mixture was added dropwise to aq. NaHCO₃solution (54.1 g in 1 L of water, 0.644 mol, 12.1 eq.) at 0° C. slowlyand adjusted to pH=8. The mixture was filtered and the aqueous layer wasextracted with dichloromethane (3×600 mL). The combined organic layerswere washed with brine, and then dried over anhydrous Na₂SO₄. Themixture was filtered and concentrated under vacuum to give the residue.The residue was purified by column chromatography on silica gel elutingwith petroleum ether: EtOAc 2:1 to give (R)-2-tert-butyl 8-methyl1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2,8(1H)-dicarboxylate(13.2 g, 55% yield) as a pale yellow solid. Analytical chiral HPLC:t_(R)=9.03 min in 15 min chromatography (Method:OD-3_(—)3_(—)5_(—)40_(—)2.5ML). LC-MS MS (ESI) m/z 452.2 [M+H]⁺. ¹H NMR(CD₃OD 400 MHz): δ 8.31 (s, 1H), 8.01 (s, 1H), 5.30-5.18 (m, 1H),4.70-4.52 (m, 1H), 4.47 (dd, J=3.2 and 12.4 Hz, 1H), 4.18 (dt, J=5.2 and11.6 Hz, 1H), 3.98 (s, 3H), 3.70-3.52 (m, 1H), 3.44 (s, 3H), 2.50-2.38(m, 1H), 1.53 (s, 9H), 1.25 (d, J=6.8 Hz, 3H), 1.06 (d, J=6.8 Hz, 3H).

Step 10:

TFA (4 mL) was added dropwise to a solution of containing(R)-2-tert-butyl 8-methyl1-isopropyl-7-(methylsulfonyl)-3,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrazine-2,8(1H)-dicarboxylate(2.0 g, 4.4 mmol) in DCM (20 mL) at rt over 2 min. The mixture wasstirred at rt for 3 h. TLC showed the starting material was consumedcompletely. The solvent was removed in vacuo at 30° C., and then DCM (10mL) was added. The mixture was neutralized with sat. aq. NaHCO₃ to pH=7.The mixture was extracted with DCM (3×20 mL) and the combined organiclayers were dried over anhydrous Na₂SO₄, filtered and concentrated undervacuum to afford (R)-methyl1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate(1.5 g, 96.4% yield) as a white solid. LC-MS m/z 351.9 [M+H]⁺, 374.0[M+Na]⁺. ¹H NMR (CDCl₃ 300 MHz): δ 8.15 (s, 1H), 8.07 (s, 1H), 4.26-4.05(m, 3H), 3.97 (s, 3H), 3.63-3.50 (m, 1H), 3.44 (s, 3H), 3.32-3.16 (m,1H), 2.85-2.66 (m, 1H), 1.16 (d, J=6.9 Hz, 3H), 0.88 (d, J=6.6 Hz, 3H).

Step 11:

A mixture of (R)-methyl1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate(0.9 g, 2.56 mmol), 2-chloro-4-(trifluoromethyl)pyrimidine (1.0 g, 5.1mmol, 2 eq.) and DIEA (1.0 g, 7.7 mmol, 3 eq.) in i-PrOH (6 mL) wasstirred in a microvave oven at 150° C. for 2 h. TLC showed the startingmaterial was consumed completely (PE:EtOAc=3:1). The solvent was removedin vacuo at 40° C., and the residue was purified by columnchromatography on silica gel eluting with PE/EtOAc=6/1 to give(R)-methyl1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate(1.0 g, 78% yield) as a white solid. LC-MS m/z 498.1 [M+H]⁺. ¹H NMR(CDCl₃ 300 MHz): δ 8.52 (d, J=4.8 Hz, 1H), 8.13 (s, 1H), 8.06 (s, 1H),6.83 (d, J=4.8 Hz, 1H), 6.06 (d, J=7.8 Hz, 1H), 5.39-5.28 (m, 1H),4.33-4.24 (m, 1H), 4.20-4.12 (m, 1H), 3.93 (s, 3H), 3.77-3.65 (m, 1H),3.39 (s, 3H), 2.52-2.38 (m, 1H), 1.25 (d, J=6.9 Hz, 3H), 1.02 (d, J=6.6Hz, 3H).

Step 12:

To a solution of (R)-methyl1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate(1.3 g, 2.6 mmol) in DCM (15 mL) was added DIBAL-H (1M in toluene, 10.4mL, 10.4 mmol, 4 eq.) at −78° C. The mixture was stirred at −78° C. for2 h. Sat. aq NH₄Cl (25 mL) was added and the mixture was filtered. Theaqueous layer was extracted with DCM (3×20 mL). The combined organiclayers were washed with brine, dried over anhydrous Na₂SO₄, filtered andconcentrated under vacuum. The residue was purified by columnchromatography on silica gel eluting with DCM/MeOH=30/1 to give apartially racemized mixture (1.1 g, 91.6% yield) as a white solid. Theracemized mixture was purified by SFC separation on a chiral column togive(R)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol(Isomer 1) (0.65 g, 54.1% yield) as a white solid and(S)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol(Isomer 2) (0.15 g, 12.5% yield) as a white solid.

Isomer 1:(R)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol:

Analytical chiral HPLC: t_(R)=8.768 min in 15 min chromatography(Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS m/z 470.1 [M+H]⁺. ¹H NMR(CDCl₃ 400 MHz): δ 8.58 (d, J=4.8 Hz, 1H), 8.13 (s, 1H), 7.89 (s, 1H),6.89 (d, J=4.8 Hz, 1H), 6.12 (d, J=8.0 Hz, 1H), 5.40-5.36 (m, 1H),5.06-5.03 (m, 2H), 4.35-4.31 (m, 1H), 4.21-4.16 (m, 1H), 3.82-3.76 (m,1H), 3.23 (s, 3H), 3.09 (t, J=6.8 Hz, 1H), 2.52-2.50 (m, 1H), 1.32 (d,J=6.8 Hz, 3H), 1.08 (d, J=6.8 Hz, 3H). ¹H NMR (CD₃OD 400 MHz): δ 8.69(d, J=4.8 Hz, 1H), 8.22 (s, 1H), 7.94 (s, 1H), 7.02 (d, J=4.8 Hz, 1H),6.05 (d, J=8.0 Hz, 1H), 5.34 (d, J=10.0 Hz, 1H), 5.10 (s, 2H), 4.50 (dd,J₁=12.0 Hz, J₂=3.6 Hz, 1H), 4.22 (td, J₁=12.0 Hz, J₂=5.2 Hz, 1H), 3.88(dddd, J₁=14.4 Hz, J₂=10.0 Hz, J₃=4.4 Hz, 1H), 3.26 (s, 3H), 2.60-2.52(m, 1H), 1.28 (d, J=6.8 Hz, 3H), 1.06 (d, J=6.8 Hz, 3H).

Isomer 1 was recrystalized as a crystalline solid by followingprocedure:

(R)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol(470 mg) was dissolved into EtOAc (3.0 mL) followed by slow addition ofhexanes (ca. 5 mL) until the solution turns cloudy. Several drops ofEtOAc were added to cause the cloudiness to disappear. The solution wasallowed to stand at rt until crystals formed. The crystalline solid wascollected by filtration. m.p. 188-189° C.

Isomer 2:(S)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazin-8-yl)methanol:

Analytical chiral HPLC: t_(R)=7.780 min in 15 min chromatography(Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS m/z 470.1 [M+H]⁺. ¹H NMR(CDCl₃ 400 MHz): δ 8.58 (d, J=5.2 Hz, 1H), 8.12 (s, 1H), 7.88 (s, 1H),6.89 (d, J=4.8 Hz, 1H), 6.11 (d, J=8.0 Hz, 1H), 5.40-5.35 (m, 1H),5.04-5.00 (m, 2H), 4.34-4.31 (m, 1H), 4.21-4.16 (m, 1H), 3.82-3.75 (m,1H), 3.22 (s, 3H), 2.52-2.50 (m, 1H), 1.31 (d, J=6.8 Hz, 3H), 1.08 (d,J=6.8 Hz, 3H).

Alternatively, a racemic mixture of methyl1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylatewas prepared by the following method.

(rac)-methyl1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylate

Step 1:

To a solution of (R)-3-isopropylpiperazin-2-one hydrochloride (2.61 g,14.62 mmol) and iPr₂NEt (7.60 mL, 43.86 mmol) in DMF (20 mL) was added asolution of 2-chloro-4-(trifluoromethyl)pyrimidine (3.47 g, 19.00 mmol)in DMF (2 mL). The resulting solution was stirred at 100° C. under N₂for 3 h at which point the reaction was deemed complete by LC-MS. Sat.aq. NH₄Cl (30 mL) was added to quench the reaction, followed by additionof EtOAc (30 mL). The EtOAc layer was separated and the aqueous layerwas extracted with EtOAc (3×20 mL). The EtOAc layers were combined,dried using Na₂SO₄ and evaporated to give nearly pure crude product.Purification on a silica cartridge using ISCO FCC eluting with 100%EtOAc gave 4.03 grams of(R)-3-isopropyl-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-2-one(96%) as a slightly orange thick oil. LC-MS m/z 289.17 [M+H]⁺. ¹H NMR(CDCl₃, 400 MHz): δ 8.52 (d, J=4.8 Hz, 1H), 6.82 (d, J=4.4 Hz, 1H), 6.56(br, 1H), 5.20 (d, J=6.8 Hz, 1H), 4.83-4.77 (m, 1H), 3.55-3.37 (m, 3H),2.49-2.41 (m, 1H), 1.15 (d, J=6.8 Hz, 3H), 1.04 (d, J=6.8 Hz, 3H).

Steps 2 and 3:

To a solution of(R)-3-isopropyl-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-2-one(986 mg, 3.42 mmol) in DMF (5 mL) was added a 2 M solution of KOtBu inTHF (2.14 mL, 4.28 mmol) dropwise at 0° C. The reaction stirred for 1 hat 0° C. and was then cooled to −78° C. In a separate flask, a solutionof methyl 2,4-difluoro-5-nitrobenzoate (928 mg, 4.28 mmol) in DMF (15mL) was cooled to −78° C. To this solution was added a solution of theabove anion via cannula at −78° C. over a 5 min period. The reaction wasallowed to warm to −50° C. and stirred at this temperature for 2 h. Sat.aq. NH₄Cl (20 mL) was added to quench the reaction, followed by EtOAc(30 mL). The EtOAc layer was separated and the aqueous layer wasextracted with EtOAc (3×15 mL). The EtOAc layers were combined, driedand evaporated to give crude(R)-methyl-2-fluoro-4-(3-isopropyl-2-oxo-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-1-yl)-5-nitrobenzoatewhich was taken on directly for the next step without furtherpurification.

LC-MS m/z 486.20 [M+H]⁺.

To a solution of the above crude (R)-methyl2-fluoro-4-(3-isopropyl-2-oxo-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-1-yl)-5-nitrobenzoatein DMF (15 mL) was added NaSO₂Me (1.05 g, 10.30 mmol) in one portion atrt. After stirring for 3 h, the reaction was deemed complete by LC-MSanalysis. Water (100 mL) was added and the mixture stirred vigorouslyfor 20 minutes before filtering off the solid material. To this solidmaterial was added 20% EtOAc in Hexanes and the mixture stirredvigorously for 10 minutes. The EtOAc/Hexanes filtrate was collected andevaporated to give 1.45 g of (R)-methyl4-(3-isopropyl-2-oxo-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-1-yl)-2-(methylsulfonyl)-5-nitrobenzoateas an off-white solid (78%, 2 steps). LC-MS m/z 546.27 [M+H]⁺. ¹H NMR(CDCl₃, 400 MHz): δ 8.59 (d, J=4.4 Hz, 1H), 8.32 (s, 1H), 8.14 (s, 1H),6.92 (d, J=5.2 Hz, 1H), 5.32 (d, J=6.8 Hz, 1H), 5.04-5.00 (m, 1H),4.12-4.02 (m, 1H), 4.03 (s, 3H), 3.88-3.80 (m, 2H), 3.44 (s, 3H),2.55-2.50 (m, 1H), 1.15 (d, J=6.8 Hz, 3H), 1.06 (d, J=6.8 Hz, 3H).

Step 4:

To a solution of(R)-methyl-4-(3-isopropyl-2-oxo-4-(4-(trifluoromethyl)pyrimidin-2-yl)piperazin-1-yl)-2-(methylsulfonyl)-5-nitrobenzoate(1.45 g, 2.66 mmol) in glacial acetic acid (17 mL) was added iron powder(445 mg, 7.97 mmol). The mixture was heated to 100° C. After 5 min, thesuspended iron dissolved into solution. The mixture was stirred at 100°C. for 48 h, at which point the flask was cooled to rt and the contentswere poured into ice. The mixture was extracted with EtOAc (2×75 mL),then the combined organic layers were washed with water (2×50 mL) andbrine (50 mL). The solution was dried over MgSO₄, filtered throughcotton, and concentrated in vacuo. The residue was purified on a silicacartridge (0% EtOAc in hexanes, then 50%) to yield 680 mg ofmethyl-1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydrobenzo[4,5]imidazo[1,2-a]pyrazine-8-carboxylateas a racemic mixture (51%). LC-MS: m/z 498.32 (M+H]⁺. ¹H NMR (CDCl₃, 400MHz): δ 8.58 (d, J=4.8 Hz, 1H), 8.20 (s, 1H), 8.12 (s, 1H), 6.90 (d,J=4.8 Hz, 1H), 6.13 (d, J=8.4 Hz, 1H), 5.39 (dd, J=4.8 Hz, 14.4 Hz, 1H),4.35 (ddd, J=1.2 Hz, 4.4 Hz, 12.0 Hz, 1H), 4.21 (dt, J=4.8 Hz, 12.0 Hz,1H), 4.00 (s, 3H), 3.78 (ddd, J=4.4 Hz, 11.6 Hz, 14.4 Hz, 1H), 3.45 (s,3H), 2.48 (sept, J=7.2 Hz, 1H), 1.32 (d, J=6.4 Hz, 3H), 1.08 (d, J=6.8Hz, 3H).

Example 3(R)-1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indoleand(S)-1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indole

Step 1:

To a solution of 6-bromo-1H-indole (5 g, 25.50 mmol) in anhydrous THF(60 mL) at 0° C. was added KH (6.80 g, 51.00 mmol, 30% wt in mineraloil). After stirring for 30 min, the mixture was cooled to −78° C. andt-BuLi (39.23 mL, 51.0 mmol, 1.3 M) was added under nitrogen. After 30min, 1,2-dimethyldisulfane (4.80 g, 51.0 mmol) was added to the mixture.The reaction mixture was stirred at −78° C. for 1 h and quenched withsat. aq NH₄Cl (30 mL) at −78° C. slowly (Caution: flame), adjusted pH=7with 1 N aqueous phosphoric acid and extracted with EtOAc (50 mL×3). Thecombined organic layers were dried over anhydrous Na₂SO₄, filtered,concentrated and purified by column chromatography on silica gel elutedwith (petroleum ether/EtOAc 10:1) to give 6-(methylthio)-1H-indole (3.9g, 93.67% yield) as a grey solid. LC-MS MS (ESI) m/z 164.1 [M+H]⁺. ¹HNMR (CDCl₃ 400 MHz): δ 8.14 (brs, 1H), 7.56 (d, J=8.0 Hz, 1H), 7.37 (s,1H), 7.18-7.11 (m, 1H), 6.56-6.51 (m, 1H), 2.52 (s, 3H).

Step 2:

To a solution of 6-(methylthio)-1H-indole (1 g, 6.13 mmol), NaOH (4.90g, 122.6 mmol) and Bu₄NHSO₄ (207.8 mg, 0.613 mmol) in dichloromethane(20 mL) was added benzenesulfonyl chloride (1.29 g, 7.36 mmol). Thereaction mixture was stirred at rt overnight. The mixture was quenchedwith water (30 mL) and extracted with CH₂Cl₂ (30 mL×3). The combinedorganic layers were dried over anhydrous Na₂SO₄, filtered, concentratedand purified by column chromatography on silica gel eluted with(petroleum ether/EtOAc 10:1) to afford6-(methylthio)-1-(phenylsulfonyl)-1H-indole (1.1 g, 59.18% yield) as awhite solid. LC-MS MS (ESI) m/z 304.0 [M+H]⁺. ¹H NMR (CDCl₃ 400 MHz): δ7.93-7.75 (m, 3H), 7.58-7.41 (m, 5H), 7.17 (dd, J₁=8.0 Hz, J₂=1.6 Hz,1H), 6.63-6.60 (m, 1H), 2.53 (s, 3H).

Step 3:

To a solution of 6-(methylthio)-1-(phenylsulfonyl)-1H-indole (890 mg,2.93 mmol) in anhydrous THF (10 mL) at 0° C. under nitrogen was addedn-BuLi (5.86 mL, 14.65 mmol, 2.5 M). After stirring for 30 min,isobutyraldehyde (1.05 g, 14.65 mmol) was added. The reaction mixturewas stirred at 0° C. for 1 h and quenched with sat. aq NH₄Cl (10 mL) at0° C. and extracted with EtOAc (20 mL×3). The combined organic layerswere dried over anhydrous sodium sulfate, filtered, concentrated andpurified by column chromatography on silica gel eluted with (petroleumether/EtOAc 20:1) to give2-methyl-1-(6-(methylthio)-1H-indol-2-yl)propan-1-one (440 mg, 64.28%yield) as a colorless oil.

LC-MS MS (ESI) m/z 234.1 [M+H]⁺. ¹H NMR (CDCl₃ 400 MHz): δ 8.86 (brs,1H), 7.52 (d, J=8.4 Hz, 1H), 7.19 (s, 1H), 7.14-7.11 (m, 1H), 7.01 (dd,J₁=8.4 Hz, J₂=1.6, 1H), 3.42-3.38 (m, 1H), 2.47 (s, 3H), 1.20 (d, J=6.8Hz, 6H).

Step 4:

To a solution of 2-methyl-1-(6-(methylthio)-1H-indol-2-yl)propan-1-one(600 mg, 2.57 mmol) and Bu₄NBr (4.12 g, 12.85 mmol) in 9 N NaOH (10 mL,cooled) was added tert-butyl(2-bromoethyl)carbamate (2.87 g, 12.85mmol). The reaction mixture was stirred at rt for 72 h. The mixture wasdiluted with water (20 mL) at 0° C. and extracted with EtOAc (20 mL×3).The combined organic layers were dried over anhydrous Na₂SO₄, filtered,concentrated and purified by column chromatography on silica gel elutingwith (petroleum ether/EtOAc 10:1) to afford tert-butyl(2-(2-isobutyryl-6-(methylthio)-1H-indol-1-yl)ethyl)carbamate (200 mg,20.66% yield) as a colorless oil. LC-MS MS (ESI) m/z 321.1 [M-56+H]⁺,277.1 [M-100+H]⁺. ¹H NMR (CDCl₃ 400 MHz): δ 7.57 (d, J=8.4 Hz, 1H), 7.38(s, 1H), 7.29 (s, 1H), 7.10 (d, J=8.4 Hz, 1H), 4.80 (brs, 1H), 4.62 (t,J=6.4 Hz, 2H), 3.58-3.42 (m, 3H), 2.58 (s, 3H), 1.38 (s, 9H), 1.24 (d,J=6.8 Hz, 6H).

Step 5:

To a solution of tert-butyl(2-(2-isobutyryl-6-(methylthio)-1H-indol-1-yl)ethyl)carbamate (200 mg,0.53 mmol) in CH₂Cl₂ (9 mL) at 0° C. was added TFA (1 mL). The reactionmixture was stirred at rt for 1 h. The mixture was concentrated (T<25°C.), treated with water (5 mL), adjusted to pH=11 with sat. NaHCO₃ andextracted with EtOAc (20 mL×3). The combined organic layers were driedover anhydrous Na₂SO₄, filtered, concentrated to afford1-(1-(2-aminoethyl)-6-(methylthio)-1H-indol-2-yl)-2-methylpropan-1-one(210 mg, 100% yield) as a colorless oil. LC-MS MS (ESI) m/z 258.8[M-18+H]⁺.

Step 6:

To a solution of1-(1-(2-aminoethyl)-6-(methylthio)-1H-indol-2-yl)-2-methylpropan-1-one(200 mg, 0.724 mmol) in MeOH (5 mL) was added Et₃N (219.3 mg, 2.172mmol). The reaction mixture was stirred at 60° C. for 1 h. NaBH₄ (82.53mg, 2.172 mmol) was added. The mixture was stirred at 60° C. for 1 h.The mixture was concentrated, treated with water (10 mL) and extractedwith EtOAc (20 mL×3). The combined organic layers were dried overanhydrous Na₂SO₄, filtered, concentrated and purified by preparative TLCon silica gel eluted with (petroleum ether/EtOAc 1:1) to afford1-isopropyl-7-(methylthio)-1,2,3,4-tetrahydropyrazino[1,2-a]indole (80mg, 42.46% yield, store at 0° C.) as a colorless oil.

LC-MS of 1-Isopropyl-7-methylsulfanyl-3,4-dihydro-pyrazino[1,2-a]indoleMS (ESI) m/z 259.1 [M+H]⁺. LC-MS of1-isopropyl-7-(methylthio)-1,2,3,4-tetrahydropyrazino[1,2-a]indole MS(ESI) m/z 261.2 [M+H]⁺. ¹H NMR (CDCl₃ 400 MHz): δ 7.41 (d, J=8.4 Hz,1H), 7.20 (s, 1H), 7.05 (dd, J₁=8.4 Hz, J₂=1.6 Hz, 1H), 6.12 (s, 1H),4.02-3.97 (m, 2H), 3.86-3.80 (m, 1H), 3.46-3.42 (m, 1H), 3.16-3.10 (m,1H), 2.48 (s, 3H), 2.32-2.27 (m, 1H), 1.09 (d, J=6.8 Hz, 3H), 0.86 (d,J=6.8 Hz, 3H).

Step 7:

To a solution of1-isopropyl-7-(methylthio)-1,2,3,4-tetrahydropyrazino[1,2-a]indole (50mg, 0.19 mmol) in PrOH (2 mL) was added2-chloro-4-(trifluoromethyl)pyrimidine (105 mg, 0.58 mmol) and DIEA (185mg, 0.96 mmol). The mixture was stirred at 100° C. for 4 h. The mixturewas concentrated under vacuum and the residue was purified bypreparative TLC to afford1-isopropyl-7-(methylthio)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indole(45 mg, 57.7% yield) as a yellow oil. LC-MS MS (ESI) m/z 407.1 [M+H]⁺.

Step 8:

To a solution of1-isopropyl-7-(methylthio)-1,2,3,4-tetrahydropyrazino[1,2-a]indole (45mg, 0.11 mmol) in MeOH (1 mL). was added NaMoO₄-2H₂O (61 mg, 0.33 mmol)and 30% H₂O₂ (67 mg, 0.55 mmol) at 0° C. The mixture was stirred at rtfor 2 h. Sat. Na₂S₂O₃ (5 mL) was added and the mixture was concentratedunder vacuum. The aqueous layer was extracted with EtOAc (3×10 mL). Thecombined organic layers were washed with brine, dried over anhydrousNa₂SO₄, filtered and concentrated under vacuum. The residue was purifiedby preparative TLC and SFC separation on a chiral column to affordisomer 1 (20.10 mg, 46.6% yield) as a white solid and isomer 2 (20.30mg, 47.1% yield) as a white solid.

Isomer 1: Analytical chiral HPLC: t_(R)=6.64 min in 15 minchromatography (Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS MS (ESI)m/z 439.0 [M+H]⁺. ¹H NMR (CD₃OD 300 MHz): δ 8.63 (d, J=4.8 Hz, 1H), 7.98(s, 1H), 7.69 (d, J=8.4 Hz, 1H), 7.57 (dd, J=1.5 and 8.4 Hz, 1H), 6.94(d, J=4.8 Hz, 1H), 6.50 (s, 1H), 5.88 (d, J=8.4 Hz, 1H), 5.11-5.07 (m,1H), 4.45-4.38 (m, 1H), 4.05 (dt, J=4.8 and 11.4 Hz, 1H), 3.91-3.83 (m,1H), 3.11 (s, 3H), 2.35-2.27 (m, 1H), 1.14 (d, J=6.6 Hz, 3H), 1.01 (d,J=6.6 Hz, 3H).

Isomer 2: Analytical chiral HPLC: t_(R)=7.37 min in 15 minchromatography (Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS MS (ESI)m/z 439.0 [M+H]⁺, 461.0 [M+Na]⁺. ¹H NMR (CD₃OD 300 MHz): δ 8.63 (d,J=4.5 Hz, 1H), 7.98 (s, 1H), 7.68 (d, J=8.4 Hz, 1H), 7.57 (dd, J=1.5 and8.4 Hz, 1H), 6.94 (d, J=4.8 Hz, 1H), 6.49 (s, 1H), 5.87 (d, J=8.1 Hz,1H), 5.10-5.06 (m, 1H), 4.44-4.37 (m, 1H), 4.03 (dt, J=4.8 and 11.4 Hz,1H), 3.90-3.80 (m, 1H), 3.11 (s, 3H), 2.34-2.26 (m, 1H), 1.14 (d, J=6.6Hz, 3H), 1.00 (d, J=6.6 Hz, 3H).

Example 4(R)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indol-8-yl)methanoland(S)-(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indol-8-yl)methanol

Step 1:

To a solution of ethyl 4-amino-2-fluorobenzoate (12 g, 65.5 mmol) in DMF(100 mL) was added NaSMe (9.17 g, 131 mmol) and the mixture was stirredat 60° C. for 20 h. After cooling to rt the reaction was diluted withH₂O and extracted with EtOAc (3×100 mL). The combined organic phaseswere washed with brine, dried over anhydrous Na₂SO₄, filtered andconcentrated in vacuo to afford ethyl 4-amino-2-(methylthio)benzoate.

To a pre-heated, 60° C. solution of ethyl 4-amino-2-(methylthio)benzoate(65 mmol) in acetic acid (150 mL) was added ICl/AcOH solution (1M, 72mL, 72 mmol) dropwise during 40 min and the temperature was maintainedat 60° C. for 3 h. After cooling to rt the reaction was diluted withEtOAc (500 mL), washed with 5% Na₂S₂O₃ solution (3×100 mL) and brine(200 mL), dried over anhydrous sodium sulfate, filtered and concentratedin vacuo. The crude product was purified by silica gel chromatography(0-20% EtOAc/Hexanes) afford ethyl 4-amino-5-iodo-2-(methylthio)benzoate(13.67 g, 53% yield).

For ethyl 4-amino-2-(methylthio)benzoate: LC-MS m/z 212 [M+H]⁺. Forethyl 4-amino-5-iodo-2-(methylthio)benzoate: LC-MS m/z 338 [M+H]⁺. ¹HNMR (400 MHz, CDCl₃): δ 8.29 (s, 1H), 6.47 (s, 1H), 4.49 (br s, 2H),4.31 (q, J=7.2 Hz, 2H), 2.38 (s, 3H), 1.37 (t, J=7.2 Hz, 3H).

Step 2:

To a solution of ethyl 4-amino-5-iodo-2-(methylthio)benzoate (13.6 g, 40mmol) in DCM (100 mL) was added Et₃N (13.8 mL, 100 mmol), followed byMsCl (7.7 mL, 100 mmol) at 0° C. After addition the mixture was stirredat rt for 2 h. 1N HCl solution (50 mL) was added to the mixture and theaqueous phase was extracted with DCM (1×100 mL). The organic solutionwas washed with brine, dried over anhydrous Na₂SO₄, filtered andconcentrated in vacuo to give ethyl5-iodo-4-(N-(methylsulfonyl)methylsulfonamido)-2-(methylthio)benzoate.

The crude reaction mixture above was dissolved into 100 mL THF. To thissolution was added TBAF solution in THF (1 M, 100 mL) and the mixturewas stirred at rt for 2 h. H₂O was added to the mixture and the aqueousphase was extracted with EtOAc (3×100 mL). The combined organic solutionwas washed with brine, dried over anhydrous Na₂SO₄, filtered andconcentrated in vacuo to afford ethyl5-iodo-4-(methylsulfonamido)-2-(methylthio)benzoate. It was used fornext step without further purification. For ethyl5-iodo-4-(N-(methylsulfonyl)methylsulfonamido)-2-(methylthio)benzoate:LC-MS m/z 494 [M+H]⁺. For ethyl5-iodo-4-(methylsulfonamido)-2-(methylthio)benzoate: LC-MS m/z 415[M+H]⁺.

Step 3:

To a solution of ethyl5-iodo-4-(methylsulfonamido)-2-(methylthio)benzoate (crude, from step 2)in dry toluene (200 mL) at 0° C. was added diisobutylaluminium hydride(1.0 M in toluene, 100 mL, 100 mmol) slowly. After addition, the mixturewas stirred at 0° C. for 3 h and quenched with methanol/H₂O (1/1). Thereaction mixture was poured into a vigorously stirred solution ofpotassium sodium tartrate (1M, 300 mL) and stirred vigorously for 2 h,after which time it settled to two clear phases. The organic layer wasseparated, and the aq layer was extracted with EtOAc (3×200 mL). Thecombined organic solution was washed with brine, dried over anhydroussodium sulfate, filtered and concentrated in vacuo. The crude productwas purified by silica gel chromatography (0-40% EtOAc/Hexanes) affordN-(4-(hydroxymethyl)-2-iodo-5-(methylthio)phenyl)methanesulfonamide(11.9 g, 80% yield for two steps). LC-MS m/z 356 [M+H]⁺. ¹H NMR (400MHz, CDCl₃): δ 7.82 (s, 1H), 7.49 (s, 1H), 4.67 (s, 2H), 2.99 (s, 3H),2.50 (s, 3H).

Step 4:

To a stirred solution ofN-(4-(hydroxymethyl)-2-iodo-5-(methylthio)phenyl)methanesulfonamide (6.4g, 17.2 mmol) and imidazole (1.76 g, 25.8 mmol) in CH₂Cl₂ (100 mL) andDMF (50 mL) at 0° C. was added tert-butyldiphenylsilyl chloride (5.8 mL,22.4 mmol). The mixture was allowed to stir at rt overnight. The mixturewas diluted with CH₂Cl₂ (100 mL), washed with 1N HCl solution, sat. aq.NaHCO₃ and brine, dried over anhydrous Na₂SO₄, filtered and concentratedin vacuo to affordN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylthio)phenyl)methanesulfonamide.It was used for next step without further purification.

A suspension of crudeN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylthio)phenyl)methanesulfonamideand mCPBA (8.9 g, 51.6 mmol) in CH₂Cl₂ (100 mL) was stirred for 2 h atrt. Sat. aq. NaHCO₃ (50 mL) and Na₂S₂O₃ (50 mL) were added and thelayers separated. The aqueous layer was extracted with CH₂Cl₂ (2×100mL). The combined organic layers were dried over anhydrous Na₂SO₄,filtered and concentrated under reduced pressure. The residue waspurified by flash chromatography over silica gel eluting withEtOAc/hexanes (3/7) to provideN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylsulfonyl)phenyl)methanesulfonamide(8.8 g, 80% yield for two steps). ForN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylthio)phenyl)methanesulfonamide:LC-MS m/z 612 [M+H]⁺. ForN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylsulfonyl)phenyl)methanesulfonamide:LC-MS m/z 644 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃): δ 8.25 (s, 1H), 8.08 (s,1H), 7.67-7.65 (m, 4H), 7.46-7.37 (m, 6H), 6.77 (s, 1H), 5.05 (s, 2H),3.11 (s, 3H), 2.83 (s, 3H), 1.12 (s, 9H).

Step 5:

PdCl₂(PPh₃)₂ (277 mg, 0.38 mmol) and CuI (73 mg, 0.38 mmol) were addedto a solution ofN-(4-(((tert-butyldiphenylsilyl)oxy)methyl)-2-iodo-5-(methylsulfonyl)phenyl)methanesulfonamide(2.45 g, 3.8 mmol) in THF (20 mL) and Et₃N (10 mL). The mixture waspurged with nitrogen for 10 min followed by addition of4-methylpent-1-yn-3-ol (745 mg, 7.6 mmol) and stirred at 65° C. for 8 h.The reaction mixture was diluted with EtOAc (50 mL) and washed with 1NHCl (50 mL). The organic layer was separated, and the aq layer wasextracted with EtOAc (3×50 mL). The combined organic solution was washedwith brine, dried over anhydrous sodium sulfate, filtered andconcentrated under reduced pressure. The residue was purified by flashchromatography over silica gel eluting with EtOAc/hexanes (3/7) toprovide1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-1,6-bis(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-ol(2.1 g, 90% yield). LC-MS m/z 614 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃): δ8.68 (s, 1H), 7.90 (s, 1H), 7.71-7.67 (s, 4H), 7.46-7.35 (m, 6H), 6.77(s, 1H), 5.21 (d, J=3.2 Hz, 2H), 6.94 (t, J=6.8 Hz, 1H), 3.22 (s, 3H),2.90 (s, 3H), 2.61 (d, J=6.8 Hz, 1H), 2.37-2.32 (m, 1H), 1.12 (s, 9H),1.05 (d, J=6.8 Hz, 3H), 1.03 (d, J=6.8 Hz, 3H). ¹³C NMR (100 MHz,CDCl₃): δ 147.25, 135.54, 135.28, 135.00, 133.66, 133.00, 132.89,129.96, 127.85, 121.68, 115.96, 108.69, 72.30, 62.98, 44.33, 41.59,32.88, 26.89, 20.23, 19.30, 17.61.

Step 6:

To a stirred solution of1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-1,6-bis(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-ol(2.3 g, 3.8 mmol) in dry CH₂Cl₂ (25 mL) was added Dess-Martin periodiane(1.94 g, 4.56 mmol) in one portion. The mixture was allowed to stir atrt for 2 h. The reaction was quenched with a solution of Na₂S₂O₃ (5 g in30 mL H₂O) and sat. aq. NaHCO₃ (40 mL). The mixture was extracted withEtOAc (3×80 mL). The combined organic solution was washed with brine,dried over anhydrous Na₂SO₄, filtered and concentrated under reducedpressure. The residue was purified by flash chromatography over silicagel eluting with EtOAc/hexanes (2/8) to provide1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-1,6-bis(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-one(2.0 g, 86% yield). LC-MS m/z 612 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃): δ8.69 (s, 1H), 8.03 (s, 1H), 7.70-7.68 (m, 4H), 7.46-7.36 (m, 6H), 7.22(s, 1H), 5.20 (s, 2H), 3.80 (s, 3H), 3.36 (m, 1H), 2.89 (s, 3H), 1.29(d, J=6.8 Hz, 6H), 1.13 (s, 9H). ¹³C NMR (100 MHz, CDCl₃): δ 197.83,141.53, 136.69, 136.05, 135.50, 135.04, 132.81, 131.14, 129.99, 127.88,123.17, 117.12, 114.21, 62.87, 44.19, 44.03, 39.09, 26.88, 19.30, 18.41.

Step 7:

To a stirred solution of1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-1,6-bis(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-one(780 mg, 1.27 mmol) in THF/methanol (15 mL/15 mL) was added Cs₂CO₃ (1.25g, 3.83 mmol) in one portion. The mixture was allowed to stir at rt for4 h and concentrated in vacuo to afford the crude product1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-6-(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-one.It was used for the next step reaction without further purification. Toa solution of crude1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-6-(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-one,2-(Boc-amino)ethyl bromide (2.8 g, 12 mmol), tetrabutylammonium iodide(235 mg, 0.63 mmol) in CH₂Cl₂/toluene (2 mL/4 mL) was added 40% NaOHaqueous solution (20 mL). The mixture was allowed to stir at rt for 20h. The reaction mixture was diluted with CH₂Cl₂ (40 mL) and washed withH₂O (50 mL). The organic layer was separated, and the aqueous layer wasextracted with CH₂Cl₂ (4×50 mL). The combined organic solution waswashed with brine, dried over anhydrous sodium sulfate, filtered andconcentrated under reduced pressure. The residue was purified by flashchromatography over silica gel eluting with CH₂Cl₂/Methanol (95/5) toprovide tert-butyl(2-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-2-isobutyryl-6-(methylsulfonyl)-1H-indol-1-yl)ethyl)carbamate(300 mg, 35% yield for two steps).

For1-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-6-(methylsulfonyl)-1H-indol-2-yl)-2-methylpropan-1-one:LC-MS m/z 556 [M+Na]⁺.

For tert-butyl(2-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-2-isobutyryl-6-(methylsulfonyl)-1H-indol-1-yl)ethyl)carbamate:LC-MS m/z 699 [M+Na]⁺. ¹H NMR (400 MHz, CDCl₃): δ 8.20 (s, 1H), 7.93 (s,1H), 7.72 (dd, J₁=8.0 Hz, J₂=1.6 Hz, 4H), 7.47-7.35 (m, 7H), 5.21 (s,2H), 4.72 (d, J=6.8 Hz, 2H), 3.55 (d, J=6.8 Hz, 2H), 3.33-3.26 (m, 1H),3.00 (s, 3H), 1.46 (s, 9H), 1.30 (d, J=6.4 Hz, 3H), 1.28 (d, J=6.4 Hz,3H), 1.11 (s, 9H).

Step 8:

To a solution of tert-butyl(2-(5-(((tert-butyldiphenylsilyl)oxy)methyl)-2-isobutyryl-6-(methylsulfonyl)-1H-indol-1-yl)ethyl)carbamate(250 mg, 0.37 mmol) in CH₂Cl₂(5.0 mL) was added trifluoroacetic acid(1.0 mL) and the mixture was allowed to stir at rt for 1 h. The excessamount of TFA was removed by azeotropic evaporation with toluene underreduced pressure. The residue was redissolved in CH₂Cl₂ (5 mL) and Et₃N(0.5 mL) was added. The reaction mixture was stirred at rt for 45 minand concentrated in vacuo. The residue was purified by flashchromatography over silica gel eluting with CH₂Cl₂/methanol (98/2) toprovide8-(((tert-butyldiphenylsilyl)oxy)methyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydropyrazino[1,2-a]indole(135 mg, 65% yield). LC-MS m/z 559 [M+H]⁺.

Step 9:

A solution of8-(((tert-butyldiphenylsilyl)oxy)methyl)-1-isopropyl-7-(methylsulfonyl)-3,4-dihydropyrazino[1,2-a]indole(140 mg, 0.25 mmol), 10% palladium on charcoal (37 mg, 0.025 mmol), andmethanol (5 mL) was stirred at rt under 1 atmosphere of hydrogen for 3h. The mixture was filtered through Celite® and the Celite® was washedthoroughly with methanol. Combined solvent was removed under reducedpressure to afford8-(((tert-butyldiphenylsilyl)oxy)methyl)-1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydropyrazino[1,2-a]indole.It was used directly without further purification. A small portion ofproduct was purified by chromatography for characterization. LC-MS m/z561 [M+H]⁺. ¹H NMR (400 MHz, CD₃OD): δ 8.00 (s, 1H), 7.73-7.70 (m, 5H),7.47-7.40 (m, 6H), 6.36 (s, 1H), 5.20 (d, J=2.0 Hz, 2H), 4.24-4.19 (m,1H), 4.11-4.00 (m, 2H), 3.52-3.47 (m, 1H), 3.20-3.13 (m, 1H), 3.03 (s,3H), 2.47-2.39 (m, 1H), 1.18 (d, J=6.8 Hz, 3H), 1.09 (s, 9H), 0.96 (d,J=6.8 Hz, 3H). ¹³C NMR (100 MHz, CDCl₃): δ 143.06, 135.68, 134.04,133.31, 131.52, 130.26, 129.79, 129.51, 127.77, 121.39, 111.22, 97.14,63.76, 59.28, 45.00, 42.94, 42.47, 31.55, 26.94, 19.72, 19.31, 16.49.

Step 10:

A mixture of 2-chloro-4-(trifluoromethyl)pyrimidine (80 mg, 0.44 mmol),8-(((tert-butyldiphenylsilyl)oxy)methyl)-1-isopropyl-7-(methylsulfonyl)-1,2,3,4-tetrahydropyrazino[1,2-a]indole(crude, from step 9), and DIEA (115 μL, 0.66 mmol) in i-PrOH/CH₂Cl₂ (2mL/1 mL) was stirred at 110° C. for 30 h. The solvent was removed underreduced pressure and the crude residue was purified by silicachromatography and SFC separation on a chiral column to give isomers of(1-isopropyl-7-(methylsulfonyl)-2-(4-(trifluoromethyl)pyrimidin-2-yl)-1,2,3,4-tetrahydropyrazino[1,2-a]indol-8-yl)methanol(75 mg, 72% yield for two steps).

Isomer 1: Analytical chiral HPLC: t_(R)=11.8 min in 15 minchromatography (Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS m/z 469[M+H]⁺. ¹H NMR (400 MHz, CD₃OD): δ 8.65 (d, J=4.8 Hz, 1H), 8.10 (s, 1H),7.78 (s, 1H), 6.95 (d, J=4.8 Hz, 1H), 6.52 (s, 1H), 5.91-5.89 (m, 1H),5.14-5.09 (m, 1H), 5.06 (s, 2H), 4.47-4.42 (m, 1H), 4.12-4.05 (m, 1H),3.94-3.86 (m, 1H), 3.26 (s, 3H), 2.37-2.29 (m, 1H), 1.17 (d, J=6.8 Hz,3H), 1.03 (d, J=6.8 Hz, 3H).

Isomer 2: Analytical chiral HPLC: t_(R)=9.7 min in 15 min chromatography(Method: AD-H_(—)5_(—)5_(—)40_(—)2.35ML). LC-MS m/z 469 [M+H]⁺. ¹H NMR(400 MHz, CD₃OD): δ 8.65 (d, J=4.8 Hz, 1H), 8.10 (s, 1H), 7.78 (s, 1H),6.95 (d, J=4.8 Hz, 1H), 6.52 (s, 1H), 5.91-5.89 (m, 1H), 5.14-5.09 (m,1H), 5.06 (s, 2H), 4.47-4.42 (m, 1H), 4.12-4.05 (m, 1H), 3.94-3.86 (m,1H), 3.26 (s, 3H), 2.37-2.29 (m, 1H), 1.17 (d, J=6.8 Hz, 3H), 1.03 (d,J=6.8 Hz, 3H).

Example 5 LXR α/β Radioligand Binding Assay

Compounds of the invention were assessed in a competition binding assaywhere different concentrations of compounds were incubated with the LXRligand binding domain (LBD) in the presence of radiolabeled LXR ligand[³H]TO901317. The amount of the LXR-LBD that complexed with [³H]T0901317was measured by scintillation proximity assay (SPA) employingnon-specific binding of LXR-LBD to poly-lysine coated Yttrium silicatebeads. Partially purified LXR α or β LBD protein (15-45 nM) wasincubated at rt for 30 min with 15 nM [³H]TO901317 (25-40 Ci/mmol) anddifferent concentrations of test compounds in 80 μL of phosphatebuffered saline (PBS) buffer containing 2.5% DMSO, 1% glycerol, 2 mMEDTA, 2 mM CHAPS and 5 mM DTT in 96-well plates. Poly-lysine SPA beads(50 μg) were added to each well and the total volume was adjusted to 120μL. The plates were shaken on an orbital shaker for 20 min and thenallowed to settle for 10 more minutes at rt before a briefcentrifugation at 2,000 rpm for 1 min. The SPA signal was measured on aMicroBeta® liquid scintillation counter (Perkin Elmer, Waltham, Mass.),and the results were used for calculating 1050 values based on the totalbinding (DMSO control) and non-specific binding (5 μM of unlabeledTO901317) controls. The K_(i) values were calculated according toequation 1, where [RL] is the final concentration of [³H]TO901317 in theassay, and the K_(d) values of 20 nM and 10 nM of TO901317 for LBDs ofLXRα and LXRβ, respectively, were determined by direct titration of theradioligand with these proteins.

$\begin{matrix}{{Ki} = \frac{{IC}\; 50}{( {1 + \frac{\lbrack{RL}\rbrack}{Kd}} )}} & (1)\end{matrix}$

Example 6 LXR Luciferase Transcriptional Reporter Gene Assay

The LXR luciferase transcriptional reporter gene assay measures theability of LXR ligands to promote transcriptional activation via theligand binding domain (LBD) of LXR. HEK293 cells were grown in DMEMmedium containing 10% FBS (Gibco®, #11995-065) and 1× PenStrep (Gibco®,#15140) at 37° C. in 5% CO₂ atmosphere. 90% confluent cells from a 150mm dish were seeded in six 100 mm dishes. The cells werebatch-transfected with an expression plasmid containing the Ga14 DNAbinding domain fused to either the LBD of LXRα or LXRβ and a luciferasereporter plasmid pG5-Luc (Promega, Madison, Wis.), which has Ga14response elements upstream of firefly luciferase gene (luc+).Transfection was accomplished with Lipofectamine™ 2000 (Gibco®)according to the manufacturer's suggested protocol. Five h followingtransfection, 15 mL of 10% charcoal-treated FBS (Hyclone, #SH30070.03)in DMEM were added to the transfected dishes without removingtransfection media, and then incubate the cells at 37° C. overnight. Thenext day, the cells from the transfected dish were trypsinized, washedwith PBS, resuspended in 10% charcoal-treated DMEM media and plated into96-well plates with 60,000 cells/100 μL per well. The cells wereincubated at 37° C. for ˜4 h before addition of 100 μL of test compoundor control ligand at different concentrations (final DMSO concentrationat 0.2%). Following incubation of the cells for 16 h with substances,the culture media were dumped and Bright-Glo™ luciferase reagent(Promega, Cat. #E2610) was added to lyse the cells and initiate theluciferase reaction. Luminescence, as a measure of luciferase activity,was detected in a plate reader (Victor2, PE-Wallac). Transcriptionalactivation in the presence of a test substance was expressed asfold-change in luminescence compared to that of cells incubated in theabsence of the substance. EC₅₀ values were calculated using the XLfit™program (IDBS, Guilford, UK).

Example 7

Compounds of the invention were tested as described in Examples 5 and 6.The biological data are presented in the table below.

LXRα LXRβ LXRα Compound BINDING K_(i) BINDING CELL LXRβ CELL No. ExampleNo. (nM) K_(i) (nM) EC50 (nM) EC50 (nM) E1 Example 1 1770 256 3370 313E2a Example 2, 318 20 340 13 isomer 1 E2b Example 2, >3330 >2500 173006940 isomer 2 E3a Example 3, 398 27 1100 87 isomer 1 E3b Example3, >3330 1750 >20000 >20000 isomer 2 E4a Example 4, 43 4 163 10 isomer 1E4b Example 4, >3330 846 >20000 >20000 isomer 2

What is claimed is:
 1. A compound of the formula:

or a pharmaceutically acceptable salt thereof.
 2. A compound of theformula:

or a pharmaceutically acceptable salt thereof.
 3. A pharmaceuticalcomposition comprising a compound of the formula:

or a pharmaceutically acceptable salt thereof; and a pharmaceuticallyacceptable carrier or diluent.
 4. The pharmaceutical composition ofclaim 3, wherein the compound is of the formula:

or a pharmaceutically acceptable salt thereof.
 5. A method of treating asubject with a disease or disorder selected from hyperlipidemia,hypercholesterolemia, hyperlipoproteinemia, hypertriglyceridemia,lipodystrophy, hepatic steatosis, nonalcoholic steatohepatitis (NASH),nonalcoholic fatty liver disease (NAFLD), hyperglycemia, insulinresistance, diabetes mellitus, dyslipidemia, atherosclerosis, gallstonedisease, acne vulgaris, dermatitis, psoriasis, contact dermatitis,atopic dermatitis, eczema, skin wounds, skin aging, photoaging,wrinkling, diabetes, Niemann-Pick disease type C, Parkinson's disease,Alzheimer's disease, inflammation, xanthoma, obesity, metabolicsyndrome, syndrome X, stroke, peripheral occlusive disease, memory loss,diabetic neuropathies, proteinuria, glomerulopathies, diabeticnephropathy, hypertensive nephropathy, IGA nephropathy, focal segmentalglomerulosclerosis, hyperphosphatemia, cardiovascular complications ofhyperphosphatemia, cancer and multiple sclerosis, comprisingadministering to the subject an effect amount of a compound of theformula:

or a pharmaceutically acceptable salt thereof.
 6. The method of claim 5,wherein the compound is of the formula:

or a pharmaceutically acceptable salt thereof.
 7. The method of claim 6,wherein the disease or disorder is atherosclerosis, Alzheimer's diseaseor dermatitis.
 8. The method of claim 7, wherein the disease or disorderis dermatitis.
 9. The method of claim 8, wherein the disease or disorderis atopic dermatitis.